Vegetated facades as environmental control systems: filtering fine particulate matter (PM2.5) for improving indoor air quality

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VEGETATED
FACADES
AS
ENVIRONMENTAL
CONTROL
SYSTEMS:

Filtering
Fine
Particulate
Matter
(PM2.5)
For
Improving
Indoor
Air
Quality

By:

Ioli
Papaioannou

A
Thesis
presented
to
the

FACULTY
OF
THE
USC
SCHOOL
OF
ARCHITECTURE

UNIVERSITY
OF
SOUTHERN
CALIFORNIA

In
Partial
Fulfillment
of
the

Requirements
for
the
Degree

MASTER
OF
BUILDING
SCIENCE

May
2013

Copyright
2013

Ioli
Papaioannou

i

ACKNOWLEDGEMENTS

I
would
like
to
express
my
gratitude
to
Professor
Douglas
Noble
for
his
support

throughout
my
thesis.
He
always
encouraged
me
to
examine
different
aspects
of
the

project
and
pursue
the
correct
answers
to
my
concerns
in
order
to
bring
my
thesis

to
completion.
He
motivated
me
to
keep
on-‐track
and
always
provided
me
with

appropriate
feedback
to
reflect
upon.
Doug,
it
was
an
honor
having
you
as
my
chair.

I
would
also
like
to
thank
Professor
Kyle
Konis.
His
involvement
from
the
initial

stages
has
made
this
thesis
possible.
His
contribution
to
my
thesis
and
his
guidance,

especially
during
the
development
of
my
research
and
experimental
methodology

was
essential
and
helped
me
to
understand
some
difficult
concepts
involved.
His

enthusiasm
was
inspiring
and
encouraging.
Kyle,
I
hope
I
will
get
the
chance
to
work

with
you
again
in
the
future.

I
gratefully
acknowledge
the
contribution
of
Pavel
Getov.
He
was
always
available
to

discuss
my
thesis
and
stimulated
me
to
develop
a
well-‐rounded
insight
of
the
topic.

He
constantly
encouraged
me
to
combine
the
experimental
and
architectural
part
of

the
study
and
guided
me
to
the
right
direction
to
do
so.
Pavel,
I
hope
we
will
keep
up

our
collaboration
to
the
future.

ii

I
am
thankful
to
Professor
Gail
Borden.
He
always
found
time
to
have
productive

discussions
about
my
progress,
my
concerns
and
answer
my
questions.
He
helped

me
comprehend
the
broad
possibilities
and
limitations
of
my
thesis
and
provided

me
with
an
alternative
point
of
view
to
take
into
consideration.
His
enthusiasm
and

advice
were
inspiring.
Gail,
it
has
been
a
pleasure
working
with
you.

I
owe
gratitude
to
Professor
Constantinos
Sioutas
and
Payam
Pakbin
from
the

Aerosol
Lab
of
the
USC
School
of
Civil
and
Environmental
Engineering.
Their

contribution
to
completing
the
experimental
part
of
my
thesis,
by
providing
me
with

the
appropriate
resources
was
crucial.
The
time
they
devoted
to
my
study
and
their

input
provided
the
scientific
background
to
successfully
complete
my
thesis.
I
hope

that
this
collaboration
will
open
an
opportunity
for
a
future
one.

A
special
thank
you
goes
to
my
family.
Without
their
support
and
encouragement

throughout
the
years
of
my
graduate
studies
none
of
this
would
be
possible.

Finally,
I
would
like
to
thank
everyone
else
who
contributed
to
the
completion
of
my

thesis
through
supporting
me
and
encouraging
me.

iii

TABLE
OF
CONTENTS

ACKNOWLEDGEMENTS
___________________________________________________________
I

LIST
OF
TABLES
_________________________________________________________________
VI

LIST
OF
FIGURES
_______________________________________________________________
VII

ABSTRACT
____________________________________________________________________
1

CHAPTER
ONE:
INTRODUCTION
___________________________________________________
3

1.1
THE
PROBLEM
______________________________________________________________
3

1.1.1
Ambient
Air
Pollution
_______________________________________________________
4

1.1.2
Indoor
Air
Pollution
________________________________________________________
5

1.1.3
Air
Pollutants
Measuring
and
Control
__________________________________________
9

1.2
RESEARCH
STATEMENT
______________________________________________________
10

1.3
BIOREMEDIATION
__________________________________________________________
11

1.3.1
Bio-‐Facades
_____________________________________________________________
12

1.3.2
Vegetated
Facades
________________________________________________________
13

1.4
NATIONAL
AMBIENT
AIR
QUALITY
STANDARDS
___________________________________
16

1.4.1
Particulate
Matter
________________________________________________________
17

1.5
AIR
FILTRATION/AIR-‐CLEANING
SYSTEMS
________________________________________
18

1.5.1
Ventilation
______________________________________________________________
20

1.5.2
ASHRAE
62.1
and
52.2
_____________________________________________________
22

1.6
OBJECTIVES
OF
THE
STUDY
AND
GOALS
_________________________________________
24

1.7
SCOPE
OF
WORK
___________________________________________________________
24

1.8
CONCLUSIONS
_____________________________________________________________
25

CHAPTER
TWO:
BACKGROUND
RESEARCH
_________________________________________
26

2.1
AMBIENT
AIR
POLLUTION
DATA
_______________________________________________
26

2.1.1
Air
Quality
Management
District
_____________________________________________
27

2.2
CONVENTIONAL
AIR
FILTRATION
______________________________________________
27

2.2.1
Materials
_______________________________________________________________
28

2.2.2
Metrics
to
measure
effectiveness
____________________________________________
30

2.2.3
MERV
and
HEPA
filters
_____________________________________________________
35

2.2.4
Energy
Consumption
______________________________________________________
36

2.3
COURSE
OF
PARTICULATE
MATTER
IN
URBAN
STREET
CANYONS
______________________
38

2.4
PHYTOREMEDIATION
_______________________________________________________
40

2.4.1
Phytofiltration
___________________________________________________________
41

2.4.2
Phytovolatalization
________________________________________________________
41

2.4.3
Phytodegradation,
Phytoextraction,
Rhizofiltration.
______________________________
42

2.4.4
Rhizoremediation
_________________________________________________________
42

2.5
DRY
DEPOSITION
AS
PART
OF
THE
PHYTOREMEDIATION
PROCESS
____________________
43

2.6
THE
FACADE
AS
A
FILTRATION
SURFACE
_________________________________________
44

2.7
PREVIOUS
RESEARCH
________________________________________________________
46

2.8
CASE
STUDIES
_____________________________________________________________
49

2.8.1
Rennselear
CASE
&
SOM,
Active
Phytoremediation
Modular
System
________________
49

iv

2.8.2
Filtration
Block
by
Elaine
Tong
_______________________________________________
50

2.8.3
“Bubble
Wrap”
by
Andrew
TÉTRAULT
/
Ben
LEE:
An
air-‐purifying
infrastructure
for
New

York
City.
____________________________________________________________________
51

2.9
CONCLUSIONS
_____________________________________________________________
53

CHAPTER
THREE:
METHODOLOGY
________________________________________________
54

3.1
PARTICULATE
MATTER
2.5
____________________________________________________
54

3.2
SYSTEM
DESCRIPTION
AND
INTEGRATION
SCHEMES
_______________________________
56

3.2.1
Vertical
Configuration
_____________________________________________________
56

3.2.2
Shelves
Configuration
_____________________________________________________
57

3.2.3
Horizontal
Configuration
___________________________________________________
58

3.3
THE
ENVIRONMENTAL
CHAMBER
______________________________________________
59

3.3.1
Plant
selection
___________________________________________________________
62

3.4
ENVIRONMENTAL
CHAMBER
FINAL
SETUP
_______________________________________
65

3.4.1
Instruments
Used
for
the
final
setup
__________________________________________
67

3.4.2
Plants
configurations
inside
the
chamber
______________________________________
68

3.4.3
Images
of
the
final
setup
___________________________________________________
71

3.5
TESTING
PROCEDURE
_______________________________________________________
74

CHAPTER
FOUR:
DATA
_________________________________________________________
75

4.1
AMBIENT
AIR
CONDITIONS
ON
THE
DAY
OF
THE
EXPERIMENT
AND
ADITIONS
TO
THE
SET-‐UP

____________________________________________________________________________
77

4.1
EXPERIMENT
RESULTS
_______________________________________________________
79

4.1.1
Control
Measurement,
Empty
Chamber
_______________________________________
79

4.1.2
Plants
at
the
sides
of
the
outlet
______________________________________________
81

4.1.3
Plants
at
the
sides
of
chamber
_______________________________________________
82

4.1.4
One
row
of
plants
_________________________________________________________
83

4.1.5
Two
rows
of
plants
________________________________________________________
84

4.1.6
Three
rows
of
plants
______________________________________________________
85

4.1.7
Five
Rows
of
plants
________________________________________________________
86

4.1.8
Chamber
full
of
plants
(8
rows)
______________________________________________
87

4.1.9
One
row
of
plants
with
wet
foliage
___________________________________________
88

4.1.10
Full
chamber,
wet
foliage
__________________________________________________
89

4.1.11
Size
Distribution
Plot
_____________________________________________________
90

4.2
CONCLUSIONS
_____________________________________________________________
92

CHAPTER
FIVE:
ANALYSIS
_______________________________________________________
93

5.1
RESULTS
ACCURACY
_________________________________________________________
93

5.2
PARTICLE
CATEGORIZATION
__________________________________________________
94

5.3
MASS
CONCENTRATION
AND
NUMBER
CONCENTRATION
___________________________
95

5.4
RESULTS
ANALYSIS
__________________________________________________________
98

5.4.1
Control
Measurement
_____________________________________________________
98

5.4.2
Vegetation
at
the
sides
of
the
opening
________________________________________
99

v

5.4.3
Screen
Configuration
______________________________________________________
99

5.4.4
Maximum
Vegetated
Surface
_______________________________________________
99

5.4.5
Area
to
removal
ratio
_____________________________________________________
100

5.4.6
Wet
Deposition
_________________________________________________________
101

5.5
COMPARATIVE
TABLE
OF
EFFICIENCY
__________________________________________
102

5.6
SIZE
DISTRIBUTION
ANALYSIS
________________________________________________
103

5.7
CONCLUSIONS
____________________________________________________________
105

CHAPTER
SIX:
CONCLUSIONS
___________________________________________________
106

6.1
THE
DESIGN
OF
EXPERIMENTAL
PROCESS
_______________________________________
106

6.2
IMPLEMENTATION
________________________________________________________
108

6.3
EXTRAPOLATION/
LARGE
SCALE
APPLICATION
___________________________________
112

6.4
BENEFITS
________________________________________________________________
114

6.5
CONCERNS
_______________________________________________________________
117

CHAPTER
SEVEN:
FUTURE
WORK
________________________________________________
122

7.1
IMPROVEMENT
OF
THE
EXPERIMENTAL
METHOD
________________________________
122

7.2
ARCHITECTURAL
APPLICATION
_______________________________________________
123

BIBLIOGRAPHY
______________________________________________________________
125

ONLINE
RESOURCES:
__________________________________________________________
127

APPENDIX
A:
DESCRIPTION
OF
THE
SETUPS
USED
AND
RESULTS
______________________
128

A.1
INITIAL
SETUP
OF
THE
ENVIRONMENTAL
CHAMBER
______________________________
128

A.1.1
Images
and
details
of
the
initial
setup
________________________________________
129

A.1.2
Sensors
________________________________________________________________
131

A.1.3
Testing
Procedure
and
Results
_____________________________________________
133

A.1.4
What
went
wrong
_______________________________________________________
137

A.2
SECOND
SETUP
___________________________________________________________
139

A.2.1
Images
of
the
second
setup
________________________________________________
140

A.2.2
Sensors
and
testing
Procedure
_____________________________________________
143

A.2.3
What
went
wrong
_______________________________________________________
145

APPENDIX
B:
CALCULATIONS
FOR
THE
ARCHITECTURAL
APPLICATION
_________________
147

APPENDIX
C:
PRELIMINARY
CFD
AND
DAYLIGHT
STUDIES
____________________________
156

C.1
AIR-‐FLOW
STUDY
__________________________________________________________
157

C.2
DAYLIGHT
STUDY
__________________________________________________________
159

vi

LIST
OF
TABLES

TABLE
1-‐1:
MOST
COMMON
AIR
POLLUTANTS
.........................................................................................
4

TABLE
1-‐2:
INDOOR
POLLUTANTS
AND
SOURCES
.......................................................................................
7

TABLE
1-‐3:
NATIONAL
AMBIENT
AIR
QUALITY
STANDARDS
.......................................................................
17

TABLE
2-‐2:
ASHRAE
52.2
MERV
PARAMETERS
....................................................................................
32

TABLE
2-‐3:
APPLICATIONS
AND
FILTER
TYPES
ACCORDING
TO
MERV
RATING
..............................................
35

TABLE
4-‐1:
CONTROL
MEASUREMENT
RESULTS
......................................................................................
80

TABLE
4-‐2:
TWO
PLANTS
AT
THE
SIDES
OF
THE
OUTLET,
RESULTS
...............................................................
81

TABLE
4-‐3:
PLANTS
AT
THE
SIDES
OF
THE
CHAMBER
RESULTS
....................................................................
82

TABLE
4-‐4:
ONE
ROW
OF
PLANTS
RESULTS
.............................................................................................
83

TABLE
4-‐5:
TWO
ROWS
OF
PLANTS
RESULTS
..........................................................................................
84

TABLE
4-‐6:
THREE
ROWS
OF
PLANTS
RESULTS
.........................................................................................
85

TABLE
4-‐7:
FIVE
ROWS
OF
PLANTS
RESULTS
...........................................................................................
86

TABLE
4-‐8:
EIGHT
ROWS
OF
PLANTS
RESULTS
.........................................................................................
87

TABLE
4-‐9:
ONE
ROW
OF
PLANTS
WET
DEPOSITION
RESULTS
....................................................................
88

TABLE
4-‐10:
EIGHT
ROWS
OF
PLANTS
WET
DEPOSITION
RESULTS
..............................................................
89

TABLE
5-‐1:
COMPARATIVE
TABLE
OF
EFFICIENCY
%
TO
AMBIENT
AIR
CONCENTRATION
AND
TO
THE
CONTROL

MEASUREMENT
.......................................................................................................................
102

TABLE
A-‐1:
PARTICLE
SIZES
...............................................................................................................
133

vii

LIST
OF
FIGURES

FIGURE
1-‐1:
BIOLOGICAL
FACADE
USING
ALGAE
TO
PRODUCE
ELECTRICITY
BY
SPLITTERWERK,
ARUP,
STRATEGIC

SCIENCE
CONSULT
OF
GERMANY
AND
COLT
INTERNATIONAL,
LOCATED
IN
GERMANY
............................
12

FIGURE
1-‐2:
LIVING
WALL
DESIGNED
BY
GSKY
FOR
AN
ESTATE
AT
MIAMI
INDIAN
CREEK
ISLAND
.....................
13

FIGURE
1-‐3:
GREEN-‐SCREEN
VEGETATED
FAÇADE
AT
THE
NATIONAL
FEDERATION
HEADQUARTERS
IN
RESTON,

VIRGINIA
.................................................................................................................................
14

FIGURE
1-‐4:
VERTICAL
GREENHOUSE,
"CENTER
OF
URBAN
AGRICULTURE"
PROPOSAL
FOR
DOWNTOWN
SEATTLE,

BY
MITHUN
..............................................................................................................................
14

FIGURE
2-‐1:
IMAGE
OF
A
PLEATED
PAPER
AIR
FILTER
................................................................................
29

FIGURE
2-‐2:
IMAGE
OF
A
FOAM
FILTER
..................................................................................................
30

FIGURE
2-‐3:
IMAGE
OF
A
FIBERGLASS
FILTERS
.........................................................................................
30

FIGURE
2-‐4:
AIR
FILTERS
COST
BREAKDOWN
..........................................................................................
37

FIGURE
2-‐5:
AIR
POLLUTANT
TRACKS
IN
URBAN
STREET
CANYONS
............................................................
39

FIGURE
2-‐6:
CATEGORIES
OF
PHYTOREMEDIATION
ACCORDING
TO
THE
DIFFERENT
PART
OF
THE
PLANT
THAT
ARE

RESPONSIBLE
............................................................................................................................
41

FIGURE
2-‐7:
ACTIVE
MODULAR
PHYTOREMEDIATION
SYSTEM
...................................................................
50

FIGURE
2-‐8:
FILTRATION
BLOCK
...........................................................................................................
51

FIGURE
2-‐9:
"BUBBLE
WRAP"
.............................................................................................................
52

FIGURE
3-‐1:
DAILY
24-‐HR
AVERAGE
AND
MAXIMUM
VALUE
OF
PM2.5
FOR
CENTRAL
LOS
ANGELES,
FROM
1ST

OF
OCTOBER
TO
21ST
OF
MARCH
................................................................................................
55

FIGURE
3-‐2:
VERTICAL
(SCREEN)
CONFIGURATION
..................................................................................
56

FIGURE
3-‐3:
VERTICAL
(LIVING
WALL)
CONFIGURATION
...........................................................................
57

FIGURE
3-‐4:
SHELVES
CONFIGURATION
.................................................................................................
58

FIGURE
3-‐5:
HORIZONTAL
(GREEN
ROOF)
CONFIGURATION
......................................................................
59

FIGURE
3-‐6:
ENVIRONMENTAL
CHAMBER
BASIC
CONFIGURATION
.............................................................
60

FIGURE
3-‐7:
ENVIRONMENTAL
CHAMBER
DIAGRAM
................................................................................
62

FIGURE
3-‐8:
FESCUE
RIDGED
LEAF
SURFACE
...........................................................................................
63

FIGURE
3-‐9:
FESCUE
ROOT
SYSTEM
......................................................................................................
64

FIGURE
3-‐10:
GROWING
PROPERTIES
ACCORDING
TO
THE
SELLER
TAG.
.......................................................
65

FIGURE
3-‐11:
ENVIRONMENTAL
CHAMBER
FINAL
SETUP
..........................................................................
66

FIGURE
3-‐12:
TWO
PLANTS
AT
THE
SIDES
OF
THE
CHAMBER,
TOTAL
AREA
OF
VEGETATION
0.22FT
2
.
.................
68

FIGURE
3-‐13:
ONE
ROW
OF
PLANTS,
TOTAL
AREA
OF
VEGETATION
0.5
FT
2
.
.................................................
69

FIGURE
3-‐14:
TWO
ROWS
OF
PLANTS,
TOTAL
AREA
OF
VEGETATION
1FT
2
.
...................................................
69

FIGURE
3-‐15:
THREE
ROWS
OF
PLANTS,
TOTAL
AREA
OF
VEGETATION
1.5FT
2
.
..............................................
69

FIGURE
3-‐16:
FIVE
ROWS
OF
PLANTS,
TOTAL
AREA
OF
VEGETATION
2.5FT
2
.
.................................................
70

FIGURE
3-‐17:
TWO
ROWS
OF
PLANTS
AT
THE
SIDES,
TOTAL
AREA
OF
VEGETATION
2FT
2
.
.................................
70

FIGURE
3-‐18:
CHAMBER
FULL
OF
PLANTS,
TOTAL
AREA
OF
VEGETATION
4.5FT
2
.
...........................................
70

FIGURE
3-‐19:

FINAL
SETUP
OF
THE
ENVIRONMENTAL
CHAMBER,
INLET
.......................................................
71

FIGURE
3-‐20:
FINAL
SETUP
OF
THE
ENVIRONMENTAL
CHAMBER,
OUTLET
AND
PUMP
.....................................
72

FIGURE
3-‐21:
THE
DUSTTRAK
AEROSOL
MONITORS
................................................................................
72

FIGURE
3-‐22:
THE
DUSTTRAK
AEROSOL
MONITORS
AND
THE
TSI
PARTICLE
COUNTER
..................................
73

FIGURE
3-‐23:
THE
TSI
ELECTROSTATIC
CLASSIFIER
..................................................................................
73

FIGURE
4-‐1:
LOCATION
OF
THE
OFF-‐CAMPUS
AEROSOL
LAB
......................................................................
76

FIGURE
4-‐2:
LOCATION
OF
THE
OFF-‐CAMPUS
AEROSOL
LAB
AND
PROXIMITY
TO
110
FREEWAY
.......................
77

FIGURE
4-‐3:
CONTROL
MEASUREMENT,
EMPTY
CHAMBER
........................................................................
80

FIGURE
4-‐4:
CONFIGURATION
1,
TWO
PLANTS
AT
THE
SIDES
.....................................................................
81

viii

FIGURE
4-‐5:
CONFIGURATION
5,
PLANTS
AT
SIDES
OF
THE
CHAMBER
..........................................................
82

FIGURE
4-‐6:
CONFIGURATION
2,
ONE
ROW
OF
PLANTS
............................................................................
83

FIGURE
4-‐7:
CONFIGURATION
3,
TWO
ROWS
OF
PLANTS
..........................................................................
84

FIGURE
4-‐8:
CONFIGURATION
4,
THREE
ROWS
OF
PLANTS
........................................................................
85

FIGURE
4-‐9:
CONFIGURATION
6,
FIVE
ROWS
OF
PLANTS
...........................................................................
86

FIGURE
4-‐10:
CONFIGURATION
7,
EIGHT
ROWS
OF
PLANTS,
FULL
CHAMBER
.................................................
87

FIGURE
4-‐11:
CONFIGURATION
2,
ONE
ROW
OF
PLANTS,
WET
LEAVES
........................................................
88

FIGURE
4-‐12:
CONFIGURATION
7,
EIGHT
ROWS
OF
PLANTS,
WET
LEAVES
.....................................................
89

FIGURE
4-‐13:
COMPARATIVE
SIZE
DISTRIBUTION
PLOT
............................................................................
91

FIGURE
5-‐1:
A
TYPICAL
AMBIENT
PARTICLE
DISTRIBUTION
AS
A
FUNCTION
OF
PARTICLE
SIZE
EXPRESSED
BY
PARTICLE

NUMBER,
SURFACE
AREA,
AND
VOLUME.
THE
LATTER
IS
EQUIVALENT
TO
A
MASS
DISTRIBUTION
WHEN

VARIATION
IN
PARTICLE
DENSITY
IS
SMALL.
VERTICAL
SCALING
IS
INDIVIDUAL
TO
EACH
PANEL
..................
97

FIGURE
5-‐2:
COMPARISON
OF
PARTICULATE
MATTER
SIZE
.......................................................................
97

FIGURE
5-‐3:
REMOVAL
EFFICIENCY
PERCENTILE
TO
VEGETATED
SURFACE
AREA
.........................................
100

FIGURE
5-‐4:
REMOVAL
PERCENTILE
PER
PARTICLE
SIZE
...........................................................................
104

FIGURE
6-‐1:
BEST
MEASURED
EFFICIENCY
AND
HIGHMERV
FILTER
COMBINATION
......................................
110

FIGURE
6-‐2:
VEGETATED
SURFACE
USED
FOR
NATURAL
VENTILATION.
.......................................................
110

FIGURE
6-‐3:
COMBINATION
OF
VEGETATED
SURFACE
AND
HIGHMERV
FILTER
FOR
MECHANICAL
VENTILATION.

............................................................................................................................................
111

FIGURE
6-‐4:
COMBINATION
OF
VEGETATED
SURFACE
AND
HIGHMERV
FILTER
FOR
NATURAL
AND
MECHANICAL

VENTILATION.
.........................................................................................................................
111

FIGURE
6-‐5:
PREDICTION
OF
THE
MAXIMUM
EFFICIENCY
OF
THE
SURFACE.
................................................
112

FIGURE
6-‐6:
REMOVAL
EFFICIENCY
ESTIMATION
FOR
0.01ΜM
TO
0.3ΜM
................................................
113

FIGURE
6-‐7:
COMPARATIVE
CHART
OF
THE
PREDICTED
AND
BEST
MEASURED
EFFICIENCY
OF
VEGETATION
AND

HIGHMERV
FILTER
COMBINATION
.............................................................................................
114

FIGURE
A-‐1:
INITIAL
SETUP
OF
THE
ENVIRONMANTAL
CHAMBER
..............................................................
128

FIGURE
A-‐2:
FINISHED
CHAMBER
.......................................................................................................
129

FIGURE
A-‐3:
ENVIRONMENTAL
CHAMBER
FULL
SET-‐UP
.........................................................................
129

FIGURE
A-‐4:
THE
ARDUINO
BOARDS
CONNECTED
TO
THE
LED
DISPLAYS
...................................................
130

FIGURE
A-‐5:
THE
SENSORS
MOUNTED
IN
THE
PVC
PIPES
........................................................................
130

FIGURE
A-‐6:
THE
ELECTRONIC
STEP-‐LESS
SPEED
CONTROL
.....................................................................
131

FIGURE
A-‐7:
AVERAGED
CONTROL
MEASUREMENT
#2,
PARTICLE
SOURCE:
CORNSTARCH,
FAN
SPEED:
HIGH
.
134

FIGURE
A-‐8:
AVERAGED
CONTROL
MEASUREMENT
#6,
PARTICLE
SOURCE:
CORNSTARCH,
FAN
SPEED:
LOW
..
134

FIGURE
A-‐9:
TEST#1
PARTICLE
SOURCE:
MATCH
SMOKE,
FAN
SPEED:
LOW
..............................................
135

FIGURE
A-‐10:
TEST#3,
PARTICLE
SOURCE:
MATCH
SMOKE,
FAN
SPEED:
HIGH
..........................................
135

FIGURE
A-‐11:
TEST#5,
PARTICLE
SOURCE:
CORNSTARCH,
FAN
SPEED:
HIGH
.............................................
136

FIGURE
A-‐12:
TEST#11,
PARTICLE
SOURCE:
CORNSTARCH,
FAN
SPEED:
LOW
............................................
136

FIGURE
A-‐13:
SECOND
SETUP
OF
THE
ENVIRONMENTAL
CHAMBER
...........................................................
139

FIGURE
A-‐14:
THE
CHAMBERS
SECOND
SETUP
AT
THE
AEROSOL
LAB
........................................................
140

FIGURE
A-‐15:
INLET,
THE
CONNECTION
TO
THE
AEROSOL
GENERATOR
AND
THE
DUSTTRAK
AEROSOL
MONITOR

MEASURING
MASS
CONCENTRATION
...........................................................................................
141

FIGURE
A-‐16:
OUTLET,
CONNECTION
TO
THE
PUMP
AND
THE
AEROSOL
DUSTTRAK
MONITOR
MEASURING
MASS

CONCENTRATION
.....................................................................................................................
141

FIGURE
A-‐17:
CONNECTION
OF
THE
TWO
CHAMBERS
............................................................................
142

FIGURE
A-‐18:
THE
AEROSOL
GENERATOR
............................................................................................
142

FIGURE
A-‐19:
MEASUREMENT
WITH
THE
CHAMBER
FULL
OF
PLANTS
........................................................
143

FIGURE
4RATION
TEST
WITH
WATER
PENETRATING
THE
CHAMBER
FROM
THE
PLYWOOD
BOTTOM
..................
143

FIGURE
B-‐1:
VOLUME
OF
AIR
USED
FOR
THE
CALCULATIONS.
...................................................................
147

ix

FIGURE
B-‐2:
DIMENSIONS
OF
A
TYPICAL
OFFICE
SPACE.
..........................................................................
148

FIGURE
B-‐3:
HORIZONTAL
SHELVES,
36"
DEPTH,
20
ROWS.
...................................................................
149

FIGURE
B-‐4:
HORIZONTAL
SHELVES,
48"
DEPTH,
15
ROWS
EQUALLY
SPACED.
...........................................
150

FIGURE
B-‐5:
HORIZONTAL
SHELVES,
48"
DEPTH,
15
ROWS.
...................................................................
150

FIGURE
B-‐6:
HORIZONTAL
SHELVES,
54”
DEPTH,
13
ROWS
EQUALLY
SPACED.
...........................................
151

FIGURE
B-‐7:
HORIZONTAL
SHELVES,
54"
DEPTH,
13
ROWS.
...................................................................
151

FIGURE
B-‐8:
HORIZONTAL
SHELVES,
60”
DEPTH,
12
ROWS
EQUALLY
SPACED.
...........................................
152

FIGURE
B-‐9:
HORIZONTAL
SHELVES,
60"
DEPTH,
12
ROWS.
...................................................................
152

FIGURE
B-‐10:
HORIZONTAL
SHELVES,
72"
DEPTH,
10
ROWS
EQUALLY
SPACED.
.........................................
153

FIGURE
B-‐11:
HORIZONTAL
SHELVES,
72"
DEPTH,
10
ROWS.
.................................................................
153

FIGURE
B-‐12:
VERTICAL
PANELS.
.......................................................................................................
154

FIGURE
C-‐1:
HORIZONTAL
SHELVES,
DEPTH
72",
SECTION
......................................................................
156

FIGURE
C-‐2:
HORIZONTAL
SHELVES
EQUALLY
SPACED,
72"
DEPTH,
SECTION
..............................................
157

FIGURE
C-‐3:
VERTICAL
PANELS
18"X18",
SECTION
................................................................................
157

FIGURE
C-‐4:
CFD
SIMULATION
RESULTS
FOR
HORIZONTAL
SHELVES,
DEPTH
72"
........................................
158

FIGURE
C-‐5:
CFD
SIMULATION
RESULTS
FOR
HORIZONTAL
SHELVES
EQUALLY
SPACED,
DEPTH
72"
................
158

FIGURE
C-‐6:
CFD
SIMULATION
RESULTS
FOR
VERTICAL
PANELS
18"X18"
..................................................
159

FIGURE
C-‐7:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
06/21,
12P.M.
..............................
160

FIGURE
C-‐8:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
06/21,
1P.M.
................................
160

FIGURE
C-‐9:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
06/21,
2P.M.
................................
160

FIGURE
C-‐10:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
06/21,
3P.M.
..............................
161

FIGURE
C-‐11:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
12/21,
12P.M.
............................
161

FIGURE
C-‐12:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
12/21,
1P.M.
..............................
161

FIGURE
C-‐13:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
12/21,
2P.M.
..............................
162

FIGURE
C-‐14:
COMPARATIVE
INTERIOR
PSEUDO-‐COLOR
RENDERING
FOR
12/21,
3P.M.
..............................
162

FIGURE
C-‐15:
DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
06/12,
12P.M.
...........................
163

FIGURE
C-‐16:
DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
06/12,
1P.M.
.............................
163

FIGURE
C-‐17:

DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
06/12,
2P.M.
............................
164

FIGURE
C-‐18:
DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
06/12,
3P.M.
.............................
164

FIGURE
C-‐19:
DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
12/12,
12P.M.
...........................
165

FIGURE
C-‐20:
DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
12/12,
1P.M.
.............................
165

FIGURE
C-‐21:
DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
12/12,
2P.M.
.............................
166

FIGURE
C-‐22:
DAYLIGHT
ON
A
POINT
GRID
ON
A
HORIZONTAL
SHELF,
FOR
06/12,
3P.M.
.............................
166

1

ABSTRACT

Air
pollution
is
a
problem
present
in
the
majority
of
the
built
environments.

Ambient
air
pollution
is
consisted
by
many
different
pollutants
which,
depending
on

their
concentration
in
the
air,
can
have
a
severe
impact
on
human
health
with
long-‐
term
implications,
and
they
can
also
deteriorate
the
surfaces
of
the
buildings
they

come
in
contact
with.
Fine
Particulate
Matter
(PM2.5)
is
amongst
them.
It
is
a

pollutant
that
tends
to
exceed
the
allowable
levels
and
that
can
have
a
severe
impact

on
human
health,
as
it
is
able
to
penetrate
deep
into
the
human
respiratory
system.

Ambient
air
pollution
is
directly
connected
with
Indoor
Air
Quality
through

infiltration
and
ventilation.
In
order
to
ensure
good
Indoor
Air
Quality
and
user

comfort,
the
air
introduced
indoors
needs
to
comply
with
specific
standards.
Air-‐
pollution
control
doesn’t
address
the
issue
of
pollutants
already
in
the
atmosphere,

and
for
reducing
those
other
filtration
methods
need
to
be
applied.
These
practices

can
be
energy
consuming,
especially
when
there
is
not
proper
maintenance,
and

sometimes
even
not
as
effective
as
expected.
Bioremediation
is
a
procedure
based

on
biological
processes,
for
filtering
pollutants
from
air,
soil
or
water,
using
living

organisms.
Phytoremediation
is
the
specific
process
of
filtering
pollutants
through

the
metabolism
of
plants.
The
use
of
vegetation
on
facades
is
being
increased
due
to

their
many
benefits
for
the
building
(shading,
insulation).
Since
the
building

envelope
is
the
part
of
the
building
that
is
in
constant
contact
with
the
ambient
air,

the
question
that
rises
is
whether
a
vegetated
façade
can
be
used
as
a
filtration

medium
for
ambient
and
indoor
air.
For
testing
this
hypothesis,
an
experimental

2

method
was
required
to
be
developed,
based
on
the
testing
method
of
conventional

filters,
to
determine
whether
the
process
of
phytofiltration,
a
form
of

phytoremediation,
can
provide
efficient
filtration
for
a
specific
pollutant,
Particulate

Matter
2.5.

3

Chapter
One:
Introduction

This
study
will
explore
the
potential
effectiveness
of
a
façade
system
that
can

contribute
in
filtering
ambient
Fine
Particulate
Matter
(PM2.5)
and
introduce
it

indoors
through
phytofiltration.
This
chapter
presents
the
problem,
the
hypothesis

and
articulates
the
strategy
for
addressing
the
problem.

1.1
THE
PROBLEM

Air
Pollution
is
the
presence
of
solids,
liquids,
or
gases
in
the
outdoor
air
in
amounts

that
are
harmful
or
detrimental
to
humans,
animal,
plants,
or
property
or
that

unreasonably
interferes
with
the
comfortable
enjoyment
of
life
and
property
1
.
The

effects
of
air
pollution
can
be
influenced
by
many
factors.
Those
are
the
weather

conditions
(wind
velocity
and
direction,
temperature,
sunlight,
precipitation),
the

topography
of
the
terrain
and
the
chemical
properties
of
the
pollutant
itself.
2

Air

pollution
can
refer
to
ambient
(outdoors)
air,
and
indoor
air.
One
of
the
most

dangerous
pollutants
that
can
have
a
severe
impact
on
human
health
is
Particulate

Matter
especially
that
consisted
of
particles
with
diameter
of
less
or
equal
to
2.5μm.

The
thesis
will
concentrate
on
addressing
the
specific
pollutant
by
taking
into

consideration
its
physical
properties.

1

Jacko,
R.
and
T.
La
Breche.
2009,
“Air
Pollution
and
Noise
Control,
in
Environmental
Engineering”
chapter
4.
2

“British
Columbia
Air
Quality”
site,
http://www.bcairquality.ca/101/air-‐quality-‐factors.html.

4

1.1.1
Ambient
Air
Pollution

Ambient
air
pollution
can
be
defined
as
the
presence
of
pollutants
in
the
outdoor
air.

These
pollutants
are
mainly
products
of
fossil
fuel
combustion;
gases
and
particles

deriving
from
chemical
and
biological
materials
used
for
agriculture
(herbicides
and

pesticides)
and
products
of
chemical
reactions
in-‐between
the
above.
The
biggest

source
of
pollutants
however
is
due
to
fossil
fuel
combustion.
Below,
a
table
with
the

most
common
air
pollutants
is
provided
(table
1-‐1).

Table
1-‐1:
Most
Common
Air
Pollutants
3

Pollutant
Description
and
Sources
Health
Impact
Environment

Particulate

Matter
(PM)

Dust,
soot

and
tiny
bits

of
solid

materials.

PM10:
Particles

smaller
than

10μm(microns)

in
diameter.

• Road
dust,

road,

construction

• Mixing
and

applying

fertilizers/

pesticides,

• Forest
fires.

Coarse
particles
irritate

the
throat
and
nose,
but

do
not
normally

penetrate
into
the
lungs.

• PM
is
the
main

source
of
haze

that
reduces

visibility,

• It
takes
hours

to
days
for

PM10
to
settle

out
of
the
air,

• Because
they

are
so
small,

PM2.5
stays
in

the
air
much

longer
than

PM10
taking

days
to
weeks

to
be
removed,

• PM
can
make

lakes
and

other
sensitive

areas
more

acidic,
causing

changes
to
the

nutrient

balance
and

harming

aquatic
life.

PM2.5:
Particles

smaller
than

2.5μm
in

diameter.

• Combustion

of
fossil

fuels
and

wood,

• Industrial

activity,

• Garbage

incineration,

• Agricultural

burning.

• Fine
particles
are
small

enough
to
make
their

way
deep
into
the

lungs.

They
are

associated
with
all

sorts
of
health

problems,
from
a
runny

nose
and
coughing
to

bronchitis,
asthma,

emphysema,

pneumonia,
heart

disease,
and
even

premature
death.

• PM2.5
is
the
worst

public
health
problem

from
air
pollution
in

the
province.
(Research

indicates
the
number

of
hospital
visits

increases
on
days
with

increased
PM
levels).

3

“British
Columbia
Air
Quality”
site,
http://www.bcairquality.ca/101/pollutants-‐table.html.

5

Ground

Level
Ozone

(O3)

Bluish
gas

with
pungent

odor

• At
ground
level
ozone
is
formed

by
chemical
reactions
between

volatile
organic
compounds

(VOCs)
and
nitrogen
dioxide

(NO2)
in
the
presence
of

sunlight,

• VOCs
and
NO2
are
released
by

burning
coal,
gasoline
and
other

fuels;
and
naturally
by
plants

and
trees

• Exposure
for
6-‐7
hours,

even
at
low

concentrations,

significantly
reduces

lung
function
and

causes
respiratory

inflammation
in

healthy
people
during

periods
of
moderate

exercise.
Can
be

accompanied
by

symptoms
such
as

chest
pain,
coughing,

nausea,
and
pulmonary

congestion.
Impacts
on

individuals
with
pre-‐
existing
heart
or

respiratory
conditions

can
be
very
serious,

• Ozone
exposure
can

contribute
to
asthma,

and
reduced
resistance

to
colds
and
other

infections.

• Ozone
can

damage
plants

and
trees,

leading
to

reduced
yields.

• Leads
to
lung

and

respiratory

damage
in

animals.

• Ozone
can
also

be
good:
the

ozone
layer

above
the

earth
(the

stratosphere)

protects
us

from
harmful

ultraviolet

rays.

Other

Pollutants

• Sulphur
Dioxide
(SO2),

• Carbon
Monoxide
(CO),

• Nitrogen
Dioxide
(NO2),

• Total
Reduced
Sulphur
(TRS),

• Volatile
Organic
Compounds

(VOCs),

• Persistent
Organic
Pollutants

(POPs),

• Lead
(Ps),

• Polycyclic
Aromatic

Hydrocarbons
(PAHs),

• Dioxins
and
furans.

Most
of
these
pollutants
come

from
combustion
and
industrial

processes
or
the
evaporation
of

paints
and
common
chemical

products.

∗ The
health
impacts
of

these
pollutants
are

varied,

∗ Sulphur
dioxide
(SO2),

for
example,
can

transform
in
the

atmosphere
to

sulphuric
acid,
a
major

component
of
acid
rain,

∗ Carbon
monoxide
is

fatal
at
high

concentrations,
and

causes
illness
at
lower

concentrations.

∗ Dioxins
and
furans
are

among
the
most
toxic

chemicals
in
the
world.

While
some
of

these
pollutants

have
local
impact

on
the

environment

(e.g.,
lead)
or
are

relatively
short

lived
(NO2)
some

are
long
lived

(POPs)
and
can

travel
the
world

on
wind
currents

in
the
upper

atmosphere.

1.1.2
Indoor
Air
Pollution

Indoor
air
pollution
refers
to
the
air
quality
in
indoor
spaces.
This
type
of
pollution

may
come
from
carbon
monoxide
(CO),
cigarette
smoke,
Particulate
Matter,

combustion
products
coming
from
sources
like
cooking
or
heating
and
Volatile

6

Organic
Compounds
(VOC)
emitted
from
building
materials
like
walls,
finishes
etc.

or
furniture.
Indoor
air
quality
(IAQ)
can
be
affected
by
the
ambient
air
pollution.

This
is
due
to
infiltration
of
outdoor
pollutants
into
indoor
spaces
but
also
through

natural
and
mechanical
ventilation.
Specifically,
Gabriel
Beko
et
al.
(2008)
4

estimated
that
[…]‘‘indoor
proportion
of
outdoor
particles’’
(IPOP)
the
annual
average

of
indoor
PM10
concentration
without
particle
filtration
to
lie
between
65%
and
95%

of
the
outdoor
PM10
level.
It
is
safe
to
conclude
that
an
important
factor
that
affects

the
concentration
of
the
ambient
air
pollutants
indoors
is
the
ventilation
of
the

building,
something
that
will
be
explained
further
in
the
following
chapter.
Below
a

table
with
common
indoor
air
pollutants
and
their
sources
is
provided
(table
1-‐2),

as
well
as
the
allowable
levels,
according
to
ASHRAE
62.1-‐2010.

4

Gabriel
Beko
et
al.
2008,
“Is
the
use
of
particle
filtration
justified?
Costs
and
benefits
of
filtration
with
regard
to

health
effects,
building
cleaning
and
occupant
productivity”,
Building
and
Environment
43,
pp.
1647-‐1657.

7

Table
1-‐2:
Indoor
Pollutants
and
Sources
5

Pollutants
Sources
NAAQS/EPA

Radon
and
radioactive

daughters
(
222
Rn)

Soil,
Ground
Water,
Building
Materials

Nitrogen
Oxides
(NOx)
Combustion
0.05ppm
[1
yr.]

Volatile
Organic

Compounds
(including

HCHO)

Building
Materials,
Carpets,
Solvents,
Paints,

Personal
Care
Products,
House
Cleaning

Products,
Room
Fresheners,
Pesticides,

Mothball,
Humans

Carbon
Monoxide
(COx)
Combustion
9ppm

35
ppm
[1
h.]*

Ozone
(O3)
Outdoor
Air,
Photocopying
Machines,

Electrostatic
Air
Cleaners

0.12
ppm
[1
h]*

0.08ppm

Sulfur
Dioxide
(SO2)
Combustion
0.03
ppm
[1
yr.]

0.14
ppm
[24
hr.]*

Particulate
Matter
Combustion
15
µm/m
3

(PM2.5)

150
µm/m
3

(PM10)

Asbestos
Building
Materials,
Hair
Drier

Bioaerosols
Air
Conditioners,
Cold
Water
Spray

Humidifiers

∗ Not
to
be
exceeded
more
than
once
per
year.

In
order
to
limit
ambient
air
pollutants
into
indoor
spaces
the
Environmental

Protection
Agency
(EPA)
proposes
three
strategies:
source
control,
improved

ventilation
and
air
cleaners.
However,
two
out
of
the
three
strategies
mentioned

above
require
some
kind
of
filtration
of
the
air
introduced
indoors,
either
this
is

done
actively
through
an
air
cleaner,
that
removes
the
pollutants
of
the
ambient
air

to
avoid
the
contamination
of
the
space
with
other
ones,
or
passively
through
some

other
system,
in
the
case
of
improved
ventilation.
Either
way,
a
filtration
system
is

required.

5

Lazaridis,
Michalis.
2011.
“First
Principles
of
Meteorology
and
Air
Pollution”,
Environmental
Pollution,
Volume

19,
pp.
255
–
304.

8

Because
people
spend
about
85%
of
their
time
indoors
6

they
are
constantly
exposed

to
these
pollutants
that
have
an
impact
on
their
health.
Ambient
air
pollution
has

also
various
serious
consequences
on
human
health.
For
example,
according
to
the

World
Health
Organization,
in
Europe,
exposure
to
Particulate
Matter
from

anthropogenic
sources,
which
is
a
pollutant
for
both
indoor
and
outdoor
spaces,
can

reduce
up
to
8.6
months
life
expectancy
and
the
increase
of
1μg/m
3

of
PM2.5
for
a

year
can
result
an
average
Lost
Life
Expectancy
of
0.22
days
per
person.
7

Apart
from
the
various
consequences
air
pollution
may
have
on
human
health
it
is

also
a
threat
for
buildings
and
mainly
for
the
building
envelope.
That
is
because
this

is
the
only
part
of
the
building
that
is
in
constant
contact
with
the
ambient
air.
This

causes
the:

“…
deterioration
of
the
external
layer
because
some
of
the
above
deposited

chemical
agents
react
with
surfaces.
Sulphur
compounds
have
been
indicted
as
the

most
critical
factors
in
this
regard,
mainly
because
they
are
often
acidic
and
can
have

high
concentrations
in
city
and
suburban
air;
however,
nitrogen
compounds
should
be

considered
as
well.
Fluxes
of
trace
gases
(e.g.,
sulphur
dioxide)
can
be
high,
especially

when
promoted
by
biological
activity.
Dissolution
by
chemical
reactions
with

contaminants
contained
in
precipitation
is
one
of
the
most
familiar
eroding
processes,

particularly
in
the
case
of
carbonaceous
stone.”
8

6

Ibid.

7

Marchwinska-‐Wyrwal,
E.
et
al.
2011.
“Impact
of
Air
Pollution
on
Public
Health,
The
Impact
of
Air
Pollution
on

Health,
Economy,
Environment
and
Agricultural
Sources”,
Dr,
Mohamed
Khallaf
(Ed.),
In
Tech.

8

Norvaišienė,
R
et
al.
2003
“Climatic
and
Air
Pollution
Effects
on
Building
Facades”
Materials
Science,
Vol.9,
No.1.

pp
102-‐105.

9

It
can
be
concluded
from
the
above,
that
it
is
necessary
to
find
a
way
to
control
and

regulate
the
unwanted
chemical
elements
in
the
atmosphere
in
polluted

environments
as
they
are
harmful
not
only
for
their
inhabitants
but
for
the
buildings

as
well.

The
most
prevalent
way
for
that
is
mechanical
air
filtration,
either
of
air

released
in
the
atmosphere,
either
of
air
entering
a
building.
However
this

procedure
is
energy
consuming
and
the
materials
used
for
it
are
usually
not

environmental
friendly.

1.1.3
Air
Pollutants
Measuring
and
Control

To
quantify
the
concentration
of
air
pollutants
in
the
atmosphere,
sensors
are

usually
being
used.
These
sensors
are
specific
to
the
pollutant
being
measured
and

can
either
indicate
values
per
time
period
(hourly,
30-‐minute
intervals
etc.)
or
they

can
simply
display
a
warning
when
the
pollutant
might
pose
a
threat
for
human

health
e.g.
smoke
detectors.
There
are
various
methods
of
measuring
air
pollution.
It

can
either
be
measured
directly
when
emitted
by
a
source
as
mass/volume
of

emission
(e.g.,
grams/m
3
)
or
mass/process
parameter
(e.g.,
grams/Kg
fuel

consumed
or
grams/second),
or
by
measuring
the
concentration
of
the
pollutant
in

a
specific
volume
of
air
(e.g.,
micrograms/m
3
).
9

Air
pollution
management
is
generally
focused
on
treating
the
emission
sources
of
air

pollutants.
These
practices
effectively
reduce
the
local
emission
of
new
air
pollutants,

9

“Clean
Air
World”
site,
http://www.cleanairworld.org/TopicDetails.asp?parent=21.

10

but
do
not
address
pollutants
already
in
the
air.
To
remove
existing
air
pollutants,

different
approaches
need
to
be
employed.
10

1.2
RESEARCH
STATEMENT

This
study
will
propose
a
system
that
can
filter
air,
through
an
alternative
biological

procedure,
for
improving
its
quality,
once
introduced
into
indoor
spaces.

The
building
envelope
can
be
used
as
an
air-‐filtration
medium
to
improve

indoor
air
quality.
-‐
Hypothesis

There
are
several
strategies
that
can
be
used
as
architectural
solutions
in
order
to

address
this
issue.
The
most
popular
passive
solution
for
controlling
ambient
air

pollutants
is
green
roofs.
However,
according
to
a
research
conducted
in
the
city
of

Chicago
by
Yang
Jun
et
al.
(2008),
even
if
the
total
area
of
all
the
building
roofs
were

to
be
turned
into
green
roofs
this
cannot
be
used
as
a
standalone
measure.
Although

costly,
the
installation
of
green
roofs
could
be
justified
in
the
long
run
if
the

environmental
benefits
were
considered.
The
green
roof
can
be
used
to
supplement
the

use
of
urban
trees
in
air
pollution
control,
especially
in
situations
where
land
and

public
funds
are
not
readily
available.

11

The
problem
in
urban
built
environments
is

that
they
are
usually
so
densely
built
that
the
option
of
creating
green
or
bioclimatic

outdoor
spaces
that
could
help
alleviate
the
problem
is
almost
impossible.
Since
the

10

Jun,
Yang
et
al.
2008.
“Quantifying
air
pollution
removal
by
green
roofs
in
Chicago”,
Atmospheric
Environment

Journal,
Vol.42,
Issue
21,
pp.
7266-‐7273.

11

Ibid.

11

horizontal
surfaces
of
buildings
are
already
being
used
in
the
form
of
green
roofs
for

addressing
this
issue
amongst
others,
the
question
is
whether
the
rest
of
the

surfaces
of
the
building
envelope
could
also
be
used
for
this
purpose.
The
roof
of
a

building
is
the
smallest
in
dimensions
surface
of
the
building
envelope
that
can
be

used,
so
if
all
of
the
vertical
surfaces
are
taken
in
advantage,
the
facades,
the
amount

of
the
surface
to
use
for
this
purpose
will
drastically
increase.
This
is
a
field
that

architects
and
engineers
have
only
recently
started
to
explore
and
not
many

projects
have
been
materialized
towards
this
direction.

1.3
BIOREMEDIATION

Bioremediation
is
the
use
of
microorganism
metabolism
to
remove
pollutants
12

from
polluted
environments.
These
organisms
are
usually
plants,
microbes,
bacteria,

algae,
and
fungi.
The
microorganisms
used
for
this
purpose
are
called

bioremediators.
Bioremediation
is
a
procedure
that
happens
naturally
as
a
part
of

an
organism’s
nutrition
functions
but
it
can
also
be
enhanced
through
fertilizers.

More
specifically,
the
biological
treatment
of
air
pollution
depends
on
aerobic

microorganisms
mostly
mesophilic
bacteria
that
feed
on
both
organic
and
inorganic

compounds
in
the
waste
gas.
The
microbes
convert
the
pollutants
into
carbon
dioxide,

water,
and
salts.
13

12

“Wikipedia”
site,
last
modified
on
22
February
2013,
http://en.wikipedia.org/wiki/Bioremediation.

13

“Pollution
Online”
site,
July
16
1998,
http://www.pollutiononline.com/doc.mvc/Biological-‐Treatment-‐of-‐Air-‐
Pollution-‐0001.

12

Most
of
the
contaminants
can
be
treated
through
this
process,
however
some
of

them,
like
heavy
metals
are
processed
with
bigger
difficulty
by
microorganisms.

Plants
are
the
most
effective
bioremediators
because
they
can
process
also
through

other
functions
happening
in
their
upper
part,
like
evapotranspiration.
The

advantages
of
this
method
are
that
it
is
cost
effective
and
it
doesn’t
require
almost

any
energy
use.
The
species
used
are
harmless
to
the
environment
and
can
be

disposed
without
creating
any
more
waste.

1.3.1
Bio-‐Facades

For
the
purposes
of
this
study
bio-‐facades
can
be
defined
as
facades
that
integrate

biological
organisms
to
benefit
the
building.
Usually
they
are
employed
to
improve

the
energy
consumption
of
the
building
by
producing
energy,
as
passive
shading

systems
or
insulating
systems,
and
to
promote
sustainability.
Most
common

applications
are
algae-‐facades
and
vegetated
façades.

Figure
1-‐1:
Biological
Facade
using
algae
to
produce
electricity
by
Splitterwerk,
ARUP,
Strategic
Science

Consult
of
Germany
and
Colt
International,
located
in
Germany
14

14

Image
source
“Inhabitat”
site,
http://inhabitat.com/splitterwerk-‐architects-‐design-‐worlds-‐first-‐algae-‐
powered-‐building-‐for-‐germany.

13

1.3.2
Vegetated
Facades

Vegetated
facades
are
bio-‐facades
that
use
plants
in
order
to
benefit
the
building.

They
can
be
distinguished
into
living
walls
and
green
facades,
depending
on
their

configuration.
For
the
purposes
of
this
study,
the
following
distinctions
can
be
made

when
describing
a
vegetated
façade.

Living
walls
use
a
structural
system
that
is
attached
on
the
building
and
includes
the

growing
substrate
of
the
plants
in
a
vertical
configuration.

Figure
1-‐2:
Living
Wall
designed
by
GSky
for
an
estate
at
Miami
Indian
Creek
Island
15

Green
facades
on
the
other
hand
are
facades
that
are
covered
by
plants
but
the

growing
substrate
is
not
necessarily
located
on
the
façade,
and
if
so
it
is
attached

horizontally
throughout
the
height
of
the
building
similar
to
a
shelving
system.

15

Image
source
“HGTV”
site:
http://www.hgtv.com/outdoor-‐rooms/design-‐trend-‐living-‐
walls/pictures/index.html.

14

Green
facades
may
also
be
facades
covered
with
ivies,
or
other
creepers.
Trellis

configurations
or
vertical
greenhouses
may
also
be
categorized
as
green
facades.

Figure
1-‐3:
Green-‐Screen
Vegetated
Façade
at
the
National
Federation
Headquarters
in
Reston,

Virginia
16

Figure
1-‐4:
Vertical
Greenhouse,
"Center
of
Urban
Agriculture"
proposal
for
downtown
Seattle,
by

Mithun
17

16

Image
source
“Continuing
Education”
site:

http://continuingeducation.construction.com/article_print.php?L=168&C=604

15

Vegetated
facades
are
getting
more
popular
as
architectural
assemblies,
as
they

benefit
buildings
in
more
than
one
way.
They
are
excellent
shading
systems
and

depending
on
the
plant
selection
they
can
contribute
significantly
in
decreasing
the

energy
consumption
of
a
building.
That
can
happen
through
selecting
plant
species

that
shed
during
the
winter
and
allow
the
sunlight
to
enter
the
building
and
bloom

during
the
summer
to
provide
shade.
Another
benefit
is
that
plants,
through

evapotranspiration,
cool
their
immediate
environment,
lowering
the
temperature
of

the
building
surface
and
therefore
reducing
the
need
for
cooling.
Finally
vegetated

facades,
in
the
form
of
living
walls,
can
also
work
as
a
noise-‐barrier
providing

acoustic
insulation
from
the
surrounding
environment,
but
that
is
more
relevant
to

the
thickness
of
the
substrate
rather
than
the
volume
of
vegetation.

There
are
also
some
considerations
when
a
vegetated
façade
is
installed.
The
most

important
is
the
maintenance
cost.
Since
they
are
composed
solely
from
living

organisms,
the
need
to
be
maintained
properly
is
very
important.
Irrigation
is
a
big

issue,
as
it
is
necessary
for
plants
to
grow
and
survive,
but
the
management
of
the

run-‐off
water
is
also
a
problem
that
needs
to
be
considered
for
filtering
or
simply
for

proper
drainage.
Furthermore,
the
irrigation
of
vertical
vegetated
surface
can
also

be
costly
and
the
higher
the
building
the
more
expensive
it
gets
to
pump
water
to

higher
floors.
Another
issue
is
that,
as
a
living
organism
it
becomes
a
part
of
a
small

ecosystem
attracting
insects,
birds
and
other
small
animals
that
may
live
in
the
city.

17

Image
source
“Ecogeek”
site:
http://node1.ecogeek-‐cdn.net/ecogeek/images/stories/mithunbig.jpg.

16

This
may
lead
to
the
contamination
of
a
part
of
the
façade,
which
can
even
spread
to

the
entire
vegetated
surface.
In
addition,
since
plants
have
a
specific
lifespan,
that
is

much
shorter
than
the
lifespan
of
the
building
or
simply
of
the
façade,
they
need
to

be
replaced
often
to
maintain
the
aesthetic
result
the
designer
was
aiming
for.
Lastly

even
in
the
case
of
a
simple
screen
with
creepers
there
is
still
a
problem
with
the

visual
comfort
of
the
users,
as
the
volume
of
the
vegetation
may
not
provide

satisfying
viewings
from
inside.

Since
plants
are
a
part
of
a
bioremediation
process,
they
can
potential
work
as
filters

cleaning
up
the
ambient
air
and
also
the
air
that
is
moved
through
the
building
to

accommodate
its
ventilating
needs.
Throughout
the
years
there
has
not
been

conducted
extensive
research
on
how
vegetation
on
buildings
may
impact
the

concentration
of
gases
or
particles
in
the
atmosphere
that
are
harmful
for
humans.

1.4
NATIONAL
AMBIENT
AIR
QUALITY
STANDARDS

The
EPA
has
set
the
National
Ambient
Air
Quality
Standards
(NAAQS)
for
ambient

air,
for
pollutants
considered
harmful
to
public
health
and
the
environment.
18

The

measuring
of
the
concentration
of
air
pollutants
in
the
ambient
air
is
usually
done
in

parts
per
million
by
volume
(ppm).
The
concentration
of
PM
is
expressed
as
mass

per
volume
of
air
(μg/m
3
).

18

“U.S.
Environmental
Protection
Agency
site”,
last
updated
on
December
14,
2012.

http://www.epa.gov/air/criteria.html.

17

Table
1-‐3:
National
Ambient
Air
Quality
Standards
19

POLLUTANT
AVERAGING
TIME
PRIMARY
STANDARD

PM10
Annual
arithmetic
mean
50
μg/m
3

24-‐h
average
150
μg/m
3

PM2.5
Annual
arithmetic
mean
15
μg/m
3

24-‐h
average
35
μg/m
3

Lead
Quarterly
average
1.5
μg/m
3

CO
1-‐h
average
35
ppm

8-‐h
average
9
ppm

SO2
Annual
arithmetic
mean
80
μg/m
3

24-‐h
average
365
μg/m
3

NO2
Annual
arithmetic
mean
0.053
ppm

O3
8-‐h
average
0.08
ppm

1.4.1
Particulate
Matter

Particulate
Matter
is
a
pollutant
that
has
a
severe
impact
on
human
health,

especially
on
sensitive
groups,
when
ambient
air
concentration
exceeds
the

allowable
levels.
"Particulate
matter,"
also
known
as
particle
pollution
or
PM,
is
a

complex
mixture
of
extremely
small
particles
and
liquid
droplets.
Particle
pollution
is

made
up
of
a
number
of
components,
including
acids
(such
as
nitrates
and
sulfates),

organic
chemicals,
metals,
and
soil
or
dust
particles.
20

According
to
the
EPA,

Particulate
Matter
can
be
distinguished
into
two
different
categories
depending
on

the
size
of
the
particles
that
comprise
it.

Particles
with
diameter
smaller
than
10μm

but
larger
than
2.5μm
are
the
“Inhalable
coarse
particles”
and
even
though
they

have
some
impact
on
human
health
the
effects
are
not
that
dangerous.
Particles
with

diameter
smaller
than
2.5µm
are
called
“fine
particles”
due
to
their
small
size.
These

particles
are
usually
products
of
combustion
from
forest
fires,
smoke
or
fossil
fuel,

or
of
chemical
reactions
between
gases
when
emitted
from
cars,
industries
or

19

Ibid.

20

Definition
from
the
“Environmental
Protection
Agency”
site,
last
updated
on
March
18
th

2013.

http://www.epa.gov/pm/.

18

plants.
Due
to
their
size,
they
pose
a
much
greater
risk
for
human
health
as
they
can

easily
penetrate
into
the
human
respiratory
system
and
create
serious
problems.
It

has
been
noticed
that
the
symptoms
of
patients
with
respiratory
problems
intensify

during
days
with
higher
levels
of
particulate
matter
in
the
atmosphere.

1.5
AIR
FILTRATION/AIR-‐CLEANING
SYSTEMS

For
the
purposes
of
this
study,
air
filtration
can
be
defined
as
the
process
of

removing
pollutants
from
the
air.
These
pollutants
are
usually
solid
particles,
such

as
dust,
mold
and
bacteria
and
chemical
contaminants
that
belong
in
Volatile

Organic
Compounds
category.
Air
filters
are
usually
applied
in
commercial
and

industrial
buildings
for
the
ventilation
of
these
spaces
to
ensure
the
IAQ.
The
air

filtered
may
be
ambient
air,
or
indoor
air
recirculating
to
be
used
again.
Another

application
for
filters
is
in
the
automotive
industry
for
ensuring
the
air
quality
in

automotive
cabins
as
well
as
controlling
the
emissions
from
car
exhausts
produced

from
the
combustion
of
fossil
fuel.
Finally,
air
filtration
may
also
be
applied
for

industrial
waste,
for
cleaning
out
the
fumes,
or
particles
occurring
during

production.

Air
filtration
is
essential
for
a
building
as
it
is
the
way
to
ensure
that
the
IAQ
will

remain
in
levels
that
are
not
threatening
for
human
health.
It
prevents
ambient
air

pollution
to
enter
the
building
and
it
cleans
the
indoor
air
from
hazardous

pollutants
in
order
to
be
recirculated.
This
is
done
through
air
cleaning
systems.

According
to
ASHRAE
62.1-‐2010,
the
term
air
cleaning
systems
means
a
device,
or
a

19

combination
of
devices
applied
to
reduce
the
concentration
of
airborne

contaminants
such
as
microorganisms,
dusts,
fumes,
inhalable
particles,
other

particulate
matter
and/or
vapors
in
the
air.
These
devices
may
be
pollutant
specific

or
they
may
be
used
to
treat
more
than
one
pollutant.
They
may
also
be
used
to

clean
either
ambient
or
indoor
air
pollutants
or
both.
As
this
study
will
concentrate

on
the
removal
of
fine
Particulate
Matter
it
is
worth
mentioning
some
of
the
most

popular
air
cleaning
systems
for
this
pollutant.

Mechanical
air
filters
is
the
most
commonly
used
method
for
cleaning
air.
These

filters
are
made
from
fibrous
materials
and
have
the
ability
to
capture
particles
on

these
fibers.
They
are
rated
according
to
their
efficiency
of
removing
Particulate

Matter.
They
can
be
distinguished
into
MERV
filters
and
HEPA
filters.
The
problem

with
most
of
these
filters
is
the
fact
that
even
though
they
are
good
in
capturing

larger
particulates,
when
it
comes
to
smaller
particles,
they
are
inefficient.

Another
way
of
removing
particles
from
the
air
is
Electronic
air
cleaners.
These

cleaners
use
a
process
called
electrostatic
attraction
to
trap
charged
particles.

According
to
the
EPA:

“They
draw
air
through
an
ionization
section
where
particles
obtain
an

electrical
charge.
The
charged
particles
then
accumulate
on
a
series
of
flat
plates

called
a
collector
that
is
oppositely
charged.
Ion
generators,
or
ionizers,
disperse

charged
ions
into
the
air,
similar
to
the
electronic
air
cleaners
but
without
a
collector.

20

These
ions
attach
to
airborne
particles,
giving
them
a
charge
so
that
they
attach
to

nearby
surfaces
such
as
walls
or
furniture,
or
attach
to
one
another
and
settle

faster.”
21

The
side
effect
of
using
this
type
of
air
cleaners
is
that
they
may
produce
ozone,

which
is
another
dangerous
pollutant
for
human
health.

The
biggest
threat
with
recirculating
indoor
air
is
re-‐contamination,
especially
in

buildings
occupied
by
more
sensitive
groups
like
schools,
offices
or
hospitals.

Therefore,
it
is
preferred
clean
outdoor
air
to
be
brought
in
rather
than
having

indoor
recirculated
air
in
heavily
occupied
buildings.

1.5.1
Ventilation

ASHRAE
62.1-‐2010
provides
the
following
definitions
and
distinctions
between

different
procedures
of
ventilation:

-‐ Ventilation
is
the
process
of
supplying
air
to
or
removing
air
from
a
space

for
the
purpose
of
controlling
air
contaminant
levels,
humidity
or

temperature
within
the
space.

-‐ Air
ventilation
is
that
portion
of
supply
air
that
is
outdoor
air
plus
any
re-‐
circulated
air
that
has
been
treated
for
the
purpose
of
maintaining

acceptable
indoor
air
quality.

21

“U.S.
Environmental
Protection
Agency”
site,
last
updated
on
July
3,
2012.

http://www.epa.gov/iaq/pubs/airclean.html.

21

-‐ Natural
ventilation
is
provided
by
thermal
wind
or
diffusion
effects

through
doors,
windows
or
other
intentional
openings
in
the
building.

The
reasons
buildings
require
ventilation
are
multiple
but
they
all
have
the
same

purpose,
to
improve
the
quality
and
the
occupant
comfort
of
the
indoor

environment.
One
reason
is
for
to
adjust
relative
humidity,
or
moisture
in
the
air.

Humidity
plays
a
great
role
into
the
occupants’
comfort
in
a
space,
but
it
is
also

related
to
the
temperature.
Generally
the
rule
is
that
the
relative
humidity
in
a
space

should
not
be
less
than
30%
to
prevent
symptoms
as
sore
eyes
or
throat
and
more

than
60%
to
prevent
the
growth
of
microorganisms.
22

Human
activity
may
also

increase
the
humidity
in
a
space
through
transpiration
or
skin
evaporation.

Another
reason
for
ventilation
is
to
increase
the
thermal
comfort
of
the
occupants

and
decrease
the
cooling
needs
of
the
building.
This
is
a
process
that
refers
to

specific
temperature
conditions,
when
the
outdoor
air
is
cooler
than
the
indoor
air.

By
letting
the
cooler
outdoor
air
enter
the
building
the
indoor
air
temperature
is

decreased.
Often,
even
if
the
temperature
decrease
is
really
small
the
wind
velocity

over
the
occupants’
skin
may
overall
improve
their
comfort
level.
Ventilation
may

also
be
used
to
cool
the
building
during
the
night
when
it
is
not
occupied
and
there

are
not
concerns
about
human
comfort.
This
process
is
called
night
flushing.

22

Lstiburek,
Joseph.
2002.
“Relative
Humidity,
Research
Report
-‐0203”,
Building
Science
Corporation
site:

http://www.buildingscience.com.

22

The
most
important
reason
for
ventilating
spaces
is
improving
IAQ.
Ventilation
is

used
to
bring
oxygen
into
an
interior
space
and
at
the
same
time
to
remove
the

hazardous
pollutants
accumulating,
by
exchanging
volumes
of
air.
The
times
that
air

needs
to
be
exchanged
in
an
hour
vary
for
building
types
and
occupancy
types.
The

method
that
the
building
is
ventilated
is
also
dependent
on
the
type
and
occupancy,

although
this
is
not
a
standard.
Buildings
generally
can
use
natural
or
mechanical

ventilation
and
this
is
distinguished
based
on
the
way
the
air
exchange
happens.

Buildings
can
also
use
a
combination
of
those
two.
Generally,
the
bigger
the
building,

or
the
amount
of
occupants,
the
bigger
the
needs
for
ventilation,
therefore
it
needs

more
frequent
air
exchanges
in
a
faster
rate
so
mechanical
ventilation
is
preferred.

However,
it
is
not
uncommon
for
residential
buildings
to
use
mechanical
ventilation

as
a
part
of
their
HVAC
system.
As
it
is
discussed
later,
mechanical
ventilation
is
a

procedure
that
consumes
energy,
especially
when
there
is
not
a
proper

maintenance,
so
the
trend
in
sustainable
buildings
is
to
be
avoided
when
possible.

1.5.2
ASHRAE
62.1
and
52.2

ASHRAE
was
founded
in
1984
and
it
is
an
organization
that
focuses
on
building

systems,
energy
efficiency,
indoor
air
quality
and
sustainability
within
the
industry.

Through
research,
standards
writing,
publishing
and
continuing
education,
ASHRAE

shapes
tomorrow’s
built
environment
today.
23

For
the
purpose
of
this
study
two
of

ASHRAE’s
standards
were
referenced
in
order
to
evaluate
the
process
and
the

results:

23

“ASHRAE”
site:
http://www.ashrae.org/about-‐ashrae/.

23

-‐ ASHRAE
62.1-‐2010:

“Standard
for
Ventilation
for
Acceptable
Indoor
Air

Quality”.
This
standard
is
used
to
ensure
that
the
IAQ
in
buildings
is

maintained
to
provide
user
comfort.
It
includes
the
outside
airflow
basis

that
buildings
need
to
have
in
order
to
comply,
the
ventilation
rates

depending
on
the
building
use
and
size
and
maintenance
guidelines
for

the
HVAC
system
(filter
changes,
damper
and
rain
pans
control).
This

standard
was
used
to
understand
how
ambient
air
introduced
into
a

building
should
be
treated
through
ventilation
(mechanical
or
natural),
in

order
to
provide
a
healthy
environment
for
the
occupants.

-‐ ASHRAE
52.2-‐2007:

“Method
of
Testing
General
Ventilation
Air-‐
Cleaning
Devices
for
Removal
Efficiency
by
Particle
Size”.
This
standard

provides
the
guidelines
for
testing
the
efficiency
of
conventional
filters

for
removing
particles
from
the
ambient
air
when
it
is
introduced
into
an

indoor
space.
Furthermore,
it
specifies
the
rating
system
used
depending

on
the
efficiency
of
the
filter
and
the
particle
size
and
based
on
that

system
the
filters
needed
for
different
building
use.
The
standard
was

used
to
understand
the
testing
procedure
that
would
be
used
for
the

thesis,
as
well
as
a
base
to
translate
and
validate
the
results
in
order
to

determine
the
efficiency
of
the
method
proposed.

24

1.6
OBJECTIVES
OF
THE
STUDY
AND
GOALS

The
current
project
focuses
on
finding
alternative
ways
of
filtering
ambient
air
in

urban
environments,
for
increasing
both
the
outdoor
and
indoor
air
quality,
as
these

two
values
are
associated
in
many
ways.
More
specifically,
the
study
will
focus
on:

-‐ Explore
and
evaluate
an
example
process
of
phytoremediation
as
a
possible

ambient
air
filtration
method.

-‐ The
development
of
an
experimental
process
to
determine
and
quantify
the

above.

-‐ The
architectural
applications
of
this
method,
a
vegetated
façade
as
an
air

filter.

1.7
SCOPE
OF
WORK

This
study
will
focus
on
examining
whether
a
vegetated
façade
system
can
perform

as
a
passive
air-‐pollution
filter.
Through
a
physical
model
and
the
construction
of
a

test-‐cell
the
amount
of
fine
Particulate
Matter
withheld
on
by
the
vegetation
will
be

quantified.
For
different
configurations
the
measurement
results
may
vary.
This

research
can
be
separated
into
three
major
parts
that
will
help
develop
the

methodology
of
the
study.
These
parts
are
the
literature
study,
the
physical
testing

and
the
analysis
of
the
results.

25

1.8
CONCLUSIONS

Air
quality
is
an
important
factor
for
life
quality
in
built
environments.
In
order
to

maintain
the
standards
suggested
by
national
organizations,
architects
need
to
take

them
into
account
when
designing.
However
in
order
to
reduce
the
concentration
of

pollutants
in
the
air,
either
ambient
or
indoor,
so
far
energy-‐consuming
methods
are

mainly
used.
Furthermore
the
materials
being
used
so
far
are
usually
not

environmental
friendly
and
they
also
require
energy
to
be
recycled
or
disposed.

This
thesis
suggests
a
specific
application
of
biological
filtration
that
can
be
applied

on
the
building
envelope
and
transform
it
into
an
air
filter
that
will
benefit
both

ambient
air
and
the
IAQ
through
ventilation.
The
study
emphasizes
on
the
process

of
phytoremediation
that
may
be
able
to
address
the
problem
and
contribute
to
its

solution.
The
proposed
system
may
have
different
integration
solutions
to
satisfy

the
architectural
and
design
needs
of
the
buildings
it
may
be
applied
on.

In
the
following
chapter
the
basic
principles
of
air
filtration
and
phytoremediation

will
be
analyzed
to
support
the
methodology
and
thinking
process
of
this
study.

26

Chapter
Two:
Background
Research

Air
quality
is
an
important
aspect
both
for
the
urban
built
environment,
as
well
as

the
spaces
that
humans
occupy.
As
the
problem
of
air
pollution
gets
more
severe
it
is

important
for
architects
to
consider
the
air
quality
of
the
spaces
they
design.
In
this

chapter
background
research
on
ambient
air
pollution,
conventional
air
filtration

methods,
phytoremediation
as
an
alternative
method
of
filtration
and
some

architectural
applications
are
presented.

2.1
AMBIENT
AIR
POLLUTION
DATA

In
order
to
have
a
better
understanding
of
the
existing
conditions
of
ambient
air

pollution
in
Los
Angeles,
especially
in
the
Central
Los
Angeles
area
that
is
the
area
of

interest
for
the
specific
project,
it
was
necessary
to
acquire
data
reporting
the
daily

values
of
fine
Particulate
Matter.
These
data
are
important
for
the
study
as
they

provide
a
better
insight
of
the
specific
pollutant’s
highest
levels
and
will
help
set
the

metric
and
define
what
the
anticipated
results
are.
The
data
were
taken
from
the
Air

Quality
Management
District.

27

2.1.1
Air
Quality
Management
District

The
Air
Quality
Management
District
(AQMD)
is
a
smog
control
agency
for
all
of

Orange
County
and
the
urban
portions
of
Los
Angeles,
Riverside
and
San
Bernardino

counties,
the
smoggiest
region
of
the
U.S.
24

The
agency
has
sensors
installed

throughout
the
areas
mentioned
above
and
provides
hourly
data
for
different

pollutants
(Particulate
Matter,
CO,
NO2
and
O3),
as
well
as
an
Air
Quality
Index
(AQI).

The
index
is
used
to
define
the
daily
air
quality
based
on
the
health
effects
that
it

may
have
on
different
demographics.
The
hourly
data
of
fine
Particulate
Matter
for

each
day
were
averaged
for
each
day
to
be
compared
with
the
NAAQS.

2.2
CONVENTIONAL
AIR
FILTRATION

The
way
that
air
filtration
has
been
handled
so
far
has
been
through
the
HVAC

system
of
buildings
by
adding
mediums
that
can
withhold
particles
as
the
air
flows

through
them.
Air
filters
are
applied
on
almost
all
building
types
to
prevent

pollutants
entering
the
conditioned
spaces.

The
basics
of
the
materials,
the
metrics

and
the
energy
consumption
of
filtering
air
through
mechanical
ventilation
will
be

explained
below.

24

“Air
Quality
Management
District”
site,
http://www.aqmd.gov.

28

2.2.1
Materials

Filters
used
in
the
building
sector,
for
controlling
Particulate
Matter,
are
made
from

fibrous
materials
that
allow
the
particles
to
stick
on
them.
The
most
common

materials
that
these
filters
are
made
of
are
pleated
paper,
foam
and
fiberglass

elements.

-‐ Pleated
Paper
Filters.
These
filters
consist
of
consecutive
layers
of
paper.

They
are
semi-‐permeable
paper
barriers
placed
perpendicular
to
airflow

in
order
to
remove
particles
from
the
air.
The
material
itself
is
quite

different
from
common
paper.
It
is
porous
and
it
is
manufactured
from

long
fibers
in
order
to
be
able
to
withhold
the
particles.

25

These
filters

are
more
common
in
the
automotive
industry,
however
there
are

applications
on
buildings
as
well.
The
advantage
of
these
filters
is
that

they
have
a
larger
total
area
compared
to
others
and
therefore
can

capture
a
bigger
amount
of
particles.

-‐ Foam
Filters.
These
filters
are
usually
made
from
polyurethane
foam.

Depending
on
the
thickness
foam
filters
can
withhold
smaller
or
larger

amounts
of
particles,
with
not
much
obstruction
of
the
airflow.
These

filters
are
also
used
in
automotive
and
aeronautical
industry,
as
well
as
in

buildings.
The
main
disadvantage
of
this
type
of
filter
is
the
material
that

it
is
manufactured
from,
as
it
is
not
environmental
friendly.

25

Definition
from
“Wikipedia”
site,
last
modified
on
10
March
2013.
http://en.wikipedia.org/wiki/Filter_paper.

29

-‐ Fiberglass
Filters.

Fiberglass
filters
are
the
most
commonly
used
for

building
applications.
They
are
manufactured
from
spun
fiberglass
and

they
are
capable
of
withholding
particles
on
their
fibers.
They
are

disposable
filters
but
amongst
the
three
categories
the
most
cost
efficient

solution
and
that
is
the
reason
they
are
preferred.

Filters,
depending
on
their
shape
can
also
be
distinguished
into
bag,
V-‐bank
and
box

filters.

Figure
2-‐1:
Image
of
a
pleated
paper
air
filter
26

26

Image
source
“Hickey
Home
Improvement”
blog,
http://shawnphickey.wordpress.com/2009/01/17/furnace-‐
air-‐filter/

30

Figure
2-‐2:
Image
of
a
foam
filter
27

Figure
2-‐3:
Image
of
a
fiberglass
filters
28

2.2.2
Metrics
to
measure
effectiveness

According
to
ASHRAE
52.2-‐2007
air-‐filters’
performance
is
determined
by

measuring
the
particle
counts
upstream
and
downstream
of
the
air-‐cleaning
device

being
tested.

The
procedure
for
testing
the
filter
is
the
following.
The
particles
are

27

Image
source
“Home-‐Air”
blog,
http://homeairnews.blogspot.com/2010/09/walmart-‐home-‐air-‐filters.html

28

Image
source
“Air
Filters
In.”
site,
http://www.filterace.com/images/Product/medium/663.jpg

31

being
separated
into
twelve
different
ranges
according
to
their
diameter.
A

laboratory
aerosol
generator
is
used
to
produce
a
controlled
aerosol
sample.
This

generator
works
similarly
to
a
paint
sprayer
and
the
diameter
of
the
particles

produced
can
be
specified.
The
tests
run
for
six
cycles,
for
each
particle
range
with
a

total
of
72
measurements.

For
each
measurement,
the
filtration
efficiency
is
stated
as
a
ratio
of
the

downstream-‐to-‐upstream
particle
count.
The
lowest
values
over
the
six
test
cycles
are

then
used
to
determine
the
Composite
Minimum
Efficiency
Curve.
Using
the
lowest

measured
efficiency
avoids
the
misinterpretation
of
averaging
and
provides
a
“worst

case”
experience
over
the
entire
test.
29

After
that
the
ranges
are
categorized
into
groups
by
four
and
the
percentages
for

each
group
are
averaged
to
determine
the
Particles
Size
Efficiency
(PSE).
30

The
Minimum
Efficiency
Reporting
Value
(MERV)
is
the
overall
reporting
value
of

the
testing
results
and
it
is
related
also
to
the
speed
velocity
the
tests
were

conducted.
To
simplify
the
results
the
MERV
is
reported
as
a
single
number
in
a
16

point
system
and
it
derives
from
the
Particles
Size
Efficiency
(PSE)
for
every
group.

The
tables
below
show
the
groups
and
particle
size
ranges
and
the
MERV

parameters
to
determine
a
filter’s
efficiency,
according
to
ASHRAE
52.2-‐2007

(tables
2-‐1
and
2-‐2):

29

“National
Air
Filtration
Association
(NAFA)”
site,
http://www.nafahq.org/understanding-‐merv/.

30

“Allergy
Clean
Environments”
site,
http://allergyclean.com/article-‐understandingmerv.htm.

32

Table
2-‐1:
ASHRAE
52.2
Particle
Size
Ranges

Range
Size
(in
microns
μm)
Group

1
From
0.30μm
to
0.40μm
E1

2
From
0.40μm
to
0.55μm

3
From
0.55μm
to
0.70μm

4
From
0.70μm
to
1.00
μm

5
From
1.00μm
to
1.30μm
E2

6
From
1.30μm
to
1.60μm

7
From
1.60μm
to
2.20μm

8
From
2.20μm
to
3.00μm

9
From
3.00μm
to
4.00μm
E3

10
From
4.00μm
to
5.50μm

11
From
5.50μm
to
7.00μm

12
From
7.00μm
to
10.00μm

Table
2-‐2:
ASHRAE
52.2
MERV
Parameters

MERV
Value
Group
E1
(Av.
Eff.
%)
Group
E2
(Av.
Eff.
%)
Group
E3
(Av.
Eff.
%)

1
N/A
N/A
E3
<
20

2
N/A
N/A
E3
<
20

3
N/A
N/A
E3
<
20

4
N/A
N/A
E3
<
20

5
N/A
N/A
20
≤
E3
<
35

6
N/A
N/A
35
≤
E3
<
50

7
N/A
N/A
50
≤
E3
<
70

8
N/A
N/A
70
≤
E3

9
N/A
E2
<
50
85
≤
E3

10
N/A
50
≤
E2
<
65
85
≤
E3

11
N/A
65
≤
E2
<
80
85
≤
E3

12
N/A
80
≤
E2
90
≤
E3

13
E1
<
75
90
≤
E2
90
≤
E3

14
75
≤
E1
<
85
90
≤
E2
90
≤
E3

15
85
≤
E1
<
95
90
≤
E2
90
≤
E3

16
95
≤
E1
95
≤
E2
90
≤
E3

33

The
air
velocities
for
which
the
tests
are
conducted
are
also
standardized
and
must

be
stated
when
the
filters
MERV
is
reported.
These
velocities
are
the
following,

according
to
ASHRAE
52.2-‐2007:

-‐ 118
FPM
(0.60
m/s)

-‐ 246
FPM
(1.25
m/s)

-‐ 295
FPM
(1.50
m/s)

-‐ 374
FPM
(1.90
m/s)

-‐ 492
FPM
(2.50
m/s)

-‐ 630
FPM
(3.20
m/s)

-‐ 748
FPM
(3.80
m/s)

The
filter’s
effectiveness
is
then
reported
as
a
MERV
value
at
an
airflow
rate
(e.g.

MERV
10
@295
FPM)

ASHRAE
62.1-‐2010
has
set
some
guidelines
for
the
filters
used
to
remove

Particulate
Matter
in
general
and
for
areas
were
the
measured
concentration
of

Particulate
Matter
exceeds
the
National
Ambient
Air
Quality
Standards.
These

guidelines
will
be
useful
for
the
study,
as
they
will
establish
a
comparison
basis
for

the
anticipated
results.

34

-‐ Particulate
Matter
Removal.
Particulate
matter
filters
or
air
cleaners

having
a
minimum
efficiency
reporting
value
(MERV)
of
not
less
than
6

when
rated
in
accordance
with
ANSI/ASHRAE
52.2
shall
be
provided

upstream
of
all
cooling
coils
or
other
devices
with
wetted
surfaces

through
which
air
is
supplied
to
an
occupiable
space.

-‐ Particulate
Matter
Smaller
than
10
μm.
(PM10).
When
the
building
is

located
in
an
area
where
the
national
standard
or
guideline
for
PM10
is

exceeded,
particle
filters
or
air
cleaning
devices
shall
be
provided
to
clean

the
outdoor
air
at
any
location
prior
to
its
introduction
to
occupied

spaces.
Particulate
matter
filters
or
air
cleaners
shall
have
a
Minimum

Efficiency
Reporting
Value
of
6
or
higher
when
rated
in
accordance
with

ANSI/ASHRAE
Standard
52.2.

-‐ Particulate
Matter
Smaller
than
2.5
μm.
(PM2.5).
When
the
building
is

located
in
an
area
where
the
national
standard
or
guideline
for
PM2.5
is

exceeded,
particle
filters
or
air
cleaning
devices
shall
be
provided
to
clean

the
outdoor
air
at
any
location
prior
to
its
introduction
to
occupied

spaces.
Particulate
matter
filters
or
air
cleaners
shall
have
a
Minimum

Efficiency
Reporting
Value
of
11
or
higher
when
rated
in
accordance
with

ANSI/ASHRAE
Standard
52.2.

35

2.2.3
MERV
and
HEPA
filters

The
table
below
shows
the
efficiency,
application
of
the
different
MERV
type
filters

(table
2-‐3):

Table
2-‐3:
Applications
and
Filter
Types
According
to
MERV
Rating
31

MERV
Rating
Efficiency
Particle
Size
Applications
Filter
Type

1-‐4
<20%
>10μm
Residential

Light
Commercial

Equipment

Fiberglass

Poly
Panel

Permanent

Metal

Foam

5-‐8
20%
to35%
3μm
to
10μm
Commercial

Industrial

Better
Residential

Paint
Booth

Pleated
Filters

Tackified

9-‐12
40%
to
75%
1μm
to
3μm
Residential
–
Best

Commercial

Telecommunications

Industrial

Best
Pleated

Rigid
Box

Rigid
Cell

Bag

13-‐16
80%
to
95%
0.3μm
to
1μm
Smoke
Removal

General
Surgery

Hospitals

Health
Care

Superior
Comm.

Rigid
Cell

Bags

V-‐Cell

Mini-‐Pleat

As
mentioned
above,
MERV
is
a
rating
system
that
is
used
for
evaluating
the

efficiency
of
an
air
filter.
The
highest
the
MERV
rate
the
better
the
effectiveness.
The

HEPA
filters
are
High
Efficiency
Particulate
Arresting
air
filters
and
are
used
for

maintaining
air
quality
in
many
building
types
(commercial,
medical,
industrial,

residential)
but
also
in
other
industries
like
the
automotive
or
the
aeronautical.

HEPA
filters
are
filters
with
a
MERV
between
17
and
19.

31

Ibid.

36

2.2.4
Energy
Consumption

The
energy
consumed
when
filtering
air
is
mainly
the
energy
needed
to
move
the

air
through
the
ducts
with
a
constant
velocity
and
that
needed
to
overcome
the

pressure
drop
across
the
filter.
Essentially
the
energy
needed
to
move
air
through
the

filter.
32

At
this
point,
the
difference
between
ventilation
and
infiltration
must
be

defined.
Ventilation,
as
defined
earlier
is
the
is
the
process
of
supplying
air
to
or

removing
air
from
a
space
for
the
purpose
of
controlling
air
contaminant
levels,

humidity
or
temperature
within
the
space.
Infiltration
on
the
other
hand
is
the

uncontrolled
inward
air
leakage
to
conditioned
spaces
through
unintentional
openings

in
ceilings,
floors
and
walls
from
unconditioned
spaces
or
the
outdoors
caused
by
the

same
pressure
differences
that
induce
exfiltration.
33

Infiltration
has
a
very
important

role
in
ventilation.
Leakages
can
increase
the
energy
consumption
of
a
ventilating

system,
not
only
in
the
effort
of
maintaining
a
constant
temperature
in
a
space,
but

also
and
more
importantly,
as
it
can
allow
ambient
air
contaminants
to
enter
the

ventilated
space.
Since
the
contaminants
are
added
to
the
ones
already
existing
in

the
space,
the
need
for
air
changes
increases
and
it
results
increased
energy

consumption
of
the
mechanical
ventilating
system.

Another
reason
why
mechanical
ventilation
can
increase
the
energy
consumption
of

a
building
is
improper
maintenance.
Even
though,
as
mentioned
above,
the

efficiency
of
air
filters
may
improve
over
time,
as
particles
are
being
withheld
on
the

32

Beko,
Gabriel
et
al.
2008.
“Is
the
use
of
particle
filtration
justified?
Costs
and
benefits
of
filtration
with
regard

to
health
effects,
building
cleaning
and
occupant
productivity”,
Building
and
Environment
43,
pp.
1647-‐1657.

33

Definition
form
ASHRAE
62.2-‐2007,
page
4.

37

fibrous
material
it
is
only
up
to
a
point
that
this
can
work
in
the
advantage
of
the

filtration
system.
If
the
filter
is
not
properly
cleaned
and
maintained,
the
amount
of

energy
needed
to
overcome
the
pressure
drop
across
the
installed
filter
and
to

maintain
the
airflow
at
desired
levels
after
a
point
only
increases.
It
also
makes

sense
that
the
larger
the
building,
the
larger
the
mechanical
ventilation
system
and

therefore
the
bigger
the
energy
consumption
of
the
system.
Energy
consumption
of

a
filter,
according
to
James
F.
Montgomery
et
al.
(2012)
34

may
also
be
dependent
on

the
filters
category
by
shape
(box,
V,
bag)
and
the
MERV
rating,
with
the
most

efficient
the
V-‐shaped
filters
for
each
corresponding
MERV.

According
to
the
National
Air
Filtration
Association
the
total
cost
of
air
filtration
can

be
described
as
follows
(figure
2-‐4):

Figure
2-‐4:
Air
Filters
Cost
Breakdown
35

34

James
F.
Montgomery
et
al.
2012.
“Predicting
the
energy
use
and
operation
of
HVAC
air
filters”,
Energy
and

Buildings
47,
pp.

643-‐650.

35

Image
source
“National
Air
Filtration
Association
(NAFA)”
site
http://www.nafahq.org/pressure-‐drop-‐
considerations-‐in-‐air-‐filtration/

38

It
is
obvious
that
the
biggest
cost
for
running
filters
in
mechanical
ventilation

systems
is
the
energy
consumed,
followed
by
the
maintenance
or
disposal
expenses.

The
main
cause
of
energy
consumption
is
as
mentioned
above
the
pressure
drop

from
one
side
of
the
filter
to
the
other
and
maintain
the
appropriate
airflow
in
the

duct.
However,
these
apply
only
to
mechanical
ventilation,
as
natural
ventilation

does
not
require
the
use
of
mechanical
parts
e.g.
fans.

2.3
COURSE
OF
PARTICULATE
MATTER
IN
URBAN
STREET
CANYONS

Another
important
aspect
for
addressing
air
pollution
in
the
urban
built

environment
is
the
course
of
Particulate
Matter
in
urban
street
canyons.
The
design

of
the
proposed
system
should
be
taking
into
consideration
these
tracks
in
order
to

provide
practical
applications.

According
to
Thomas
A.M.
Pugh
et
al.
(2012)
urban
street
canyons
are
poorly

ventilated
which
results
to
high
concentration
of
air
pollutants
due
to
the
fact
that

air
recirculates
in
these
areas
and
is
not
exchanged
with
cleaner.
In
urban
street

canyons
the
emissions
from
automobiles
increases
the
problem,
even
though
the

pollutants
from
these
sources
are
reduced
by
dispersion,
this
is
limited
at
the
street-‐
level
by
in-‐canyon
air
recirculation
and
low
wind
speeds.
36

Through
Computational

Fluid
Dynamics
simulations
the
tracks
of
pollutants
are
shown
in
the
following

diagram
(figure
2-‐5).

36

Pugh,
Thomas
A.M.
et
al.
2012.
”Effectiveness
of
Green
Infrastructure
for
Improvement
of
Air
Quality
in
Urban

Street
Canyons”,
Environmental
Science
and
Technology
46,
pp.
7692-‐7699.

39

Figure
2-‐5:
Air
Pollutant
Tracks
in
Urban
Street
Canyons
37

From
this
diagram
it
can
be
concluded
that
the
vertical
surfaces
of
buildings
can

potentially
accept
a
large
amount
of
particles.
A
percentile
of
the
pollutants
also

passes
above
the
canyon
through
the
roof
levels.

So
far
the
basics
of
mechanical
ventilation
and
air
filtration
have
been
explained

along
with
the
main
concerns
why
this
method
of
filtering
air
might
not
be
as
energy

efficient,
or
environmentally
friendly
as
possible.
This
study
proposes
a
method
for

turning
the
vertical
surfaces
of
a
building
into
filtration
mediums
through
the

method
of
phytoremediation.
The
basic
principles
of
phytoremediation
along
with

some
research
and
architectural
case
studies
are
presented
in
the
following
section.

37

Image
source

“InTech”
site,
http://www.intechopen.com/source/html/16145/media/image4.png

40

2.4
PHYTOREMEDIATION

The
method
proposed,
applied
and
tested
in
this
study
is
phytoremediation.
This

method
was
chosen
because
it
is
a
sustainable
way
of
filtering
contaminants.
It
does

not
require
the
amount
of
energy
as
conventional
air
purification
trough
filters
and

the
materials
used
are
far
less
harmful
to
the
environment,
as
they
do
not
have

embodied
energy
or
demand
energy
to
be
recycled
or
disposed.
Furthermore
it
is
a

method
that
is
aesthetically
pleasing,
especially
when
it
has
architectural

applications
and,
as
mentioned
above,
it
can
also
benefit
buildings
in
several
other

ways.

Phytoremediation
is
the
use
of
plants
and
their
associated
microbes
for

environmental
cleanup.

38

That
may
refer
to
soil
cleanup,
water
cleanup
or
air

cleanup.
Different
parts
or
biological
operations
of
the
plant
can
perform
the

cleaning
process.
Each
of
these
represents
a
different
type
of
phytoremediation
that

can
be
divided
into
the
following
categories.

38

Elizabeth
Pilon-‐Smits,
2005.“Phytoremediation,
Annual
Review
of
Plant
Biology”,
Vol.
56, pp 15–39.

41

Figure
2-‐6:
Categories
of
Phytoremediation
according
to
the
different
part
of
the
plant
that
are

responsible
39

2.4.1
Phytofiltration

Phytofiltration
is
the
process
of
using
the
morphological
characteristics
of
plants
to

trap
or
capture
Particulate
Matter
from
ambient
air.
40

These
may
include
the
leaf

morphology
and
surface
area,
the
foliage
orientation
or
the
bark
of
the
plant.

2.4.2
Phytovolatalization

Phytovolatilization
refers
to
the
uptake
and
transpiration
of
contaminants,
primarily

organic
compounds,
by
plants.
The
contaminant,
present
in
the
water,
or
soil,
is

taken
up
by
the
plant,
passes
through
the
plant
or
is
modified
by
the
plant,
and
is

released
to
the
atmosphere
(evaporates
or
vaporizes).
41

This
type
of

phytoremediation
is
mainly
used
for
removing
heavy
metals
from
soil
or
water.

39

Image
source:
Yang,
Hua
and
Liu,
Yanju.
2011.
“The
Impact
of
Air
Pollution
on
Health,
Economy,
Environment

and
Natural
Sources,
Chapter
13:
Phytoremediation
on
Air
Pollution”,
Dr.
Mohamed
Khallaf
(Ed.)
In
Tech

Publications.

40

Yang,
Hua
and
Liu,
Yanju,
“The
Impact
of
Air
Pollution
on
Health,
Economy,
Environment
and
Natural
Sources,

Chapter
13:
Phytoremediation
on
Air
Pollution”,
Dr.
Mohamed
Khallaf
(Ed.)
In
Tech
Publications.

41

“University
of
Hawaii
System”
site,
http://www.hawaii.edu/abrp/Technologies/phyvola.html

42

2.4.3
Phytodegradation,
Phytoextraction,
Rhizofiltration.

Phytodegradation
is
the
breakdown
of
contaminants
taken
up
by
plants
through

metabolic
processes
within
the
plant
or
the
breakdown
of
contaminants

surrounding
the
plant
through
the
effect
of
compounds
(such
as
enzymes)
produced

by
the
plants.
42

This
method
is
used
mainly
to
control
herbicides,
ammunition
waste

and
chlorinated
solvents.

Phytoextraction,
also
called
phytoaccumulation,
refers
to
the
uptake
of
metals
from

soil
by
plant
roots
into
aboveground
portions
of
plants.
43

The
plants
used
for
this

method
are
usually
“hyperaccumulators”
44

which
means
they
can
uptake
larger

amounts
of
contaminants
compared
to
other
species.
This
method
is
mainly
used
for

soil
cleanup
from
metals.

Rhizofiltration,
is
the
removal
by
plant
roots
of
contaminants
in
surface
water,

wastewater,
or
extracted
ground
water,
through
adsorption
or
precipitation
onto

the
roots,
or
absorption
into
the
roots.
45

2.4.4
Rhizoremediation

Rhizoremediation
or
rhizodegradation
is
the
breakup
of
pollutants
by
bacteria,

microbes
and
other
microorganisms
located
in
the
root
system
of
a
plant.
This

42

“Biology
Online”
site,
last
updated
on
June
23,
2008.
http://www.biology-‐
online.org/articles/phytoremediation-‐a-‐lecture/phytodegradation.html

43

“United
Nations
Environment
Program”
site,

http://www.unep.or.jp/ietc/publications/freshwater/fms2/2.asp

44

Wendy
Ann
Peer
et
al.
2006
“Molecular
Biology
of
Homeostasis
and
Detoxification:
Phytoremediation
and

hyperaccumulator
plants”,
Topics
in
Current
Genetics,
Vol.14,
pp.
229-‐340.

45

Pivetz.
Bruce
E.
2011.
“Phytoremediation
of
Contaminated
Soil
and
Ground
Water
at
Hazardous
Waste
Sites”,

EPA/540/S-‐01/500.

43

method
is
used
to
treat
pollutants,
mostly
organic
compounds
that
are
hydrophobic

and
therefore
cannot
enter
the
plant.
46

The
study
will
focus
on
examining
phytofiltration
as
a
possible
filtering
method
and

the
potential
effectiveness
of
a
vegetated
façade
to
reduce
the
levels
of
Fine

Particulate
Matter
through
this
process.

2.5
DRY
DEPOSITION
AS
PART
OF
THE
PHYTOREMEDIATION
PROCESS

Another
process
that
needs
to
be
mentioned
and
is
part
of
the
phytofiltration

process
is
dry
deposition.

“Dry
deposition
is
the
process
by
which
atmospheric
trace
chemicals
are

transferred
by
air
motions
to
the
surface
of
the
Earth.
Gravitational
settling
affects

deposition
of
particles,
especially
those
larger
than
a
few
micrometers
in
diameter.

Emission
of
gases
and
particles
from
the
surface
can
be
the
major
factor
in
the
dry
air

surface
exchange
of
some
gases
and
particles.”
47

46
“Colorado
State
University”
site,

http://rydberg.biology.colostate.edu/Phytoremediation/2008%20websites/Alford%20Phytostimulation%20W
ebpage/rhizoremediation.htm.

47

Wesely
M.L.
and
B.B.
Hicks.
2000.
“A
review
of
the
current
status
of
knowledge
on
dry
deposition”,

Atmospheric
Environment
34,
pp.
2261-‐2282.

44

The
particles
that
are
deposited
on
the
plant
surfaces
can
then
be
absorbed
by
the

stomata
of
the
plants
and
be
broken
down
by
its
metabolism
(phytovolitalization).
It

is
phytofiltration
that
particulate
matter
in
air
is
reduced
through
the
surface
of

plants.
48

2.6
THE
FACADE
AS
A
FILTRATION
SURFACE

The
building
envelope
is
the
component
of
a
building
that
is
in
continuous
contact

with
the
exterior
environmental
conditions.
Its
function
is
very
similar
to
the
human

skin;
it
should
protect
the
interior
to
ensure
that
the
building
is
operating
smoothly,

but
at
the
same
time
it
should
be
able
to
filter
exterior
elements,
like
daylight
or

ventilation,
and
allow
them
to
penetrate
the
interior
to
only
improve
the
interior

conditions.
The
filtering
should
be
happening
to
benefit
the
building,
and
similar
to

the
human
body,
regulate
the
energy
that
under
other
circumstances
would
be

required
to
maintain
the
occupants
comfort.

Air
pollution
is
an
issue
that
must
be
constantly
be
addressed
in
urban
centers.
The

conventional
methods
are
energy
consuming
and
usually
not
environmental

friendly.
Since
the
facades
are
already
being
used
to
regulate
the
buildings

operations
in
matters
of
day
lighting,
energy
consumption,
or
acoustics
it
makes

sense
that
they
can
also
be
used
as
a
filter
for
improving
air
quality.
Architects
have

employed
green
roofs
for
attempting
to
address
this
issue.
However,
research
has

48

Hua
Yang
and
Yanju
Lie.
2011.
“Phytoremediation
on
Air
Pollution:
The
Impact
of
Air
Pollution
on
Health

Economy,
Environment
and
Agricultural
Sources”,
Dr.
Mohamed
Khallaf
(Ed.)
In
Tech
Publications.

45

shown
that
even
when
the
total
surface
area
of
all
the
roofs
in
the
built
environment

is
used,
this
can
only
contribute
slightly
to
alleviating
the
problem.
This
makes
sense

when
looking
at
the
air
pollution
tracks
in
an
urban
street
canyon,
as
green
roofs
fail

to
address
the
amount
of
air
recirculating
in
them,
trapped
between
buildings.

Green
roofs
can
be
used
to
treat
roof
level
air
streams.

But
for
the
air
circulating
in

urban
street
canyons
it
is
obvious
that
the
vertical
surface
of
a
building
should
also

be
employed.
Furthermore
since
green
roofs
have
been
found
to
have
an
effect
in

treating
air
pollution
but
not
enough
surface
area,
it
makes
sense
to
try
to
engage

the
entire
surface
of
the
building
envelope.
The
total
area
of
the
vertical
surfaces
of
a

building
is
usually
much
larger
than
the
area
of
the
roof
by
itself,
a
fact
that
makes

façades
a
great
possible
solution
in
treating
air
pollution.

The
technology
of
turning
facades
into
vegetated
surfaces
has
advanced
and
offers

many
different
options
for
the
architect.
Apart
from
the
visual
pleasing
effect
that
a

green
surface
might
provide
for
the
occupants
of
the
built
environment,
it
is

possible
that
through
biological
processes
(phytoremediation)
the
plants
used
can

also
contribute
into
increasing
air
quality.
Below
are
presented
the
results
of
some

research
conducted
to
determine
the
effects
of
different
phytoremediation
types,
as

well
as
some
architectural
suggestions
for
utilizing
this
process.

46

2.7
PREVIOUS
RESEARCH

The
effectiveness
of
dry
deposition
depends
on
the
configuration
of
the
surface
that

it
is
happening.
According
to
Thomas
A.M.
Pugh,
et
al.
(2012)
vertical
vegetated

surfaces
in
urban
street
canyons
can
contribute
significantly
into
reducing
the

amount
of
certain
pollutants,
NO2
and
Particulate
Matter.
The
researchers

developed
a
mathematical
model
and
used
Computational
Fluid
Dynamics
(CFD)

simulation
in
order
to
determine
the
concentrations
and
courses
of
particles
in

urban
street
canyons.
CiTTy-‐Street,
another
mathematical
model,
was
used
to

calculate
the
deposition
of
particles
on
the
vegetated
facades.
Taking
into
account

different
sizing
scenarios
of
surfaces
the
study
tried
to
estimate
the
deposition

velocities
of
the
pollutants
on
them.
The
term
of
deposition
velocity
in
aerosol

physics
is
defined
as
process
by
which
aerosol
particles
collect
or
deposit

themselves
on
solid
surfaces
decreasing
their
concentration
in
the
air.

49

The

amount
of
particles
withheld
onto
vegetated
surfaces
is
proved
to
be
considerably

larger
(from
15%
to
23%)
compared
to
brick
walls,
depending
on
the
wind
velocity.

This
research
also
suggest
that
vegetated
vertical
surfaces
consist
a
much
more

effective
way
of
controlling
these
contaminants
compared
to
horizontal
surfaces

(green
roofs).

50

Similar
studies
have
been
done
toward
that
direction
to
explore
the

phytoremediation
properties
of
plants
for
treating
air
pollutants.
Hua
Yang
et
al.

49

“Wikipedia”
site,
last
modified
on
27
March,
2013.

http://en.wikipedia.org/wiki/Deposition_(aerosol_physics)

50

Pugh,
Thomas
A.M.
et
al.
2012.
”Effectiveness
of
Green
Infrastructure
for
Improvement
of
Air
Quality
in
Urban

Street
Canyons”,
Environmental
Science
and
Technology
46,
pp.
7692-‐7699.

47

(2011)
tried
to
determine
the
removal
of
benzene
and
toluene,
a
benzene
bi-‐
product,
by
using
various
species
of
ornamental
houseplants
by
the
process
of

phytoremediation.
These
gases
are
common
indoor
air
pollutants
and
are
classified

as
Volatile
Organic
Compounds.

The
experiment
included
eight
cylindrical
Plexiglas

chambers
where
the
gases
were
carried
through
pipes.
The
results
showed
that
the

plants
were
able
to
remove
more
than
30%
of
the
hazardous
gases
at
a
6-‐hour

sampling,
depending
on
the
concentration
level
at
the
beginning
of
the
experiment

and
the
total
leaf
area.
51

Another
research
by
Sharyn
E.
Gaskin
et
al.
(2010)
tested
the
rhizoremediation

properties
of
various
species
of
Australian
grasses
for
removing
hydrocarbons,

coming
from
diesel
oil.

For
this
experiment,
a
mix
of
diesel
oil
and
engine
fuel
with

soil
that
would
represent
the
concentration
of
these
chemicals
into
soil
located
near

a
mine
site.
Native
perennial
grasses
seeds
where
chosen
for
the
experiment
and

planted
into
the
contaminated
soil.
Sampling
of
rhizosphere
soil
was
conducted

periodically
for
a
total
of
100
days.

The
results
showed
that,
depending
on
the
grass

species
there
was
efficiency
up
to
88%
of
removing
the
chemicals
within
the
first

two
weeks
of
the
experiment.
52

Other
studies
53

have
also
indicated
that
other
grass

types,
like
rye
grass,
are
able
to
effectively
remove
oil
contaminants
from
soil.

51

Hua
Yang
and
Yanju
Lie.
2011.
“Phytoremediation
on
Air
Pollution:
The
Impact
of
Air
Pollution
on
Health

Economy,
Environment
and
Agricultural
Sources”,
Dr.
Mohamed
Khallaf
(Ed.)
In
Tech
Publications.

52

Sharyn
E.
et
al.
2010.
“Rhizoremediation
of
hydrocarbon
contaminated
soil
using
Australian
native
grasses”,

Science
of
Total
Environment
408,
pp.
3683-‐3688.

53

Voulliamoz
J.
and
Mike
M.
2001.
“Effect
of
compost
in
phytoremediation
of
diesel-‐contaminated
soils”,
Water

Science
Technology,
43,
pp.
291-‐5.

48

The
Central
Pollution
Control
Board
of
Delhi
published
in
2007
published
a
research

study
exploring
the
phytoremediation
of
particulate
matter
through
the
dust

capturing
ability
of
native
outdoors
plant
species.
The
study
evaluated
the
dust

deposition
ability
of
different
plants
in
several
categories,
herbs,
shrubs
and
trees,

throughout
the
year.
The
sites
selected
were
located
in
areas
with
high

concentrations
of
Particulate
Matter
in
the
ambient
air,
near
factories,
mines,
and
in

areas
with
heavy
traffic.
The
methodology
used
in
this
study
to
evaluate
the

phytoremediation
properties
of
these
plants
was
the
following.
Leaves
of
plants

were
collected
during
a
two-‐year
time
period
to
evaluate
the
amount
of
dust

absorption
throughout
the
various
seasonal
and
climatic
changes.
The
study

concluded
that
for
the
specific
process
of
phytoremediation,
two
factors
have
the

most
important
role
for
its
effectiveness,
the
morphology
and
the
anatomical

features
of
the
leaves.
These
are
related
to
two
important
biological
functions
of

plants,
photosynthesis
and
transpiration.
Other
factors
that
may
affect
the
dust

capturing
ability
of
a
plant
and
are
also
connected
to
the
leaf
shape
are
the
water

movement
on
the
leaf,
the
seasonal
shedding
and
the
metabolism
rate.
The
product

of
the
research
was
a
list
of
plants
depending
on
their
dust
capturing
properties.

49

2.8
CASE
STUDIES

Even
though
there
has
been
a
lot
of
research
on
the
thermal
and
acoustic
properties

of
vegetated
facades,
there
has
not
been
substantial
research
concerning
the

pollution
control
properties
that
a
green
wall
might
have.
Some
architectural

applications
of
these
methods
are
the
following:

2.8.1
Rennselear
CASE
&
SOM,
Active
Phytoremediation
Modular
System

The
Rennselear
School
of
Architecture
in
collaboration
with
SOM
architects

introduced
the
Active
Phytoremediation
Modular
System
(Figure
2-‐7).
This
system

is
used
as
an
interior
filter
of
Volatile
Organic
Compounds
and
uses
the
method
of

rhizoremediation.
The
system
has
integrated
small
fans
into
its
structure
that
push

the
air
through
the
roots
of
the
plants
and
filter
it.
The
study
showed
that
the

amount
of
VOC’s
treated
by
a
four-‐module
configuration
of
the
system
was

equivalent
to
the
result
of
800-‐1200
houseplants
54
.
The
measurements
were

conducted
in
a
Plexiglas
chamber
were
the
effectiveness
of
a
single
module
was

tested.
The
chamber
consisted
of
two
separate
compartments,
were
the
air
quality

was
measured,
the
intake,
were
controlled
amounts
of
VOC’s
were
introduced
in
the

air
and
the
outtake,
were
the
filtered
air
was
measured.

54

Gerfen
Katie.
August
11,
2009,
“Active
Phytoremediation
Wall
System”,
Architect
Magazine
site,

http://www.architectmagazine.com/green-‐technology/active-‐phytoremediation-‐wall-‐system.aspx

50

Figure
2-‐7:
Active
Modular
Phytoremediation
System
55

2.8.2
Filtration
Block
by
Elaine
Tong

The
filtration
block
(figure
2-‐8)
is
a
modular
structural
unit
that
performs
as
an

interior
filtration
system.
The
way
it
works
is
that
it
instead
of
a
mechanical
filter,
it

uses
common
houseplants
and
through
the
method
of
rhizoremediation
it
purifies

indoor
air.
The
modules
can
be
installed
on
the
ceiling
or
on
a
structural
wall.
They

are
constructed
from
Plexiglas
to
allow
light
exposure
and
they
are
sustained

through
a
water-‐misting
infrastructure.
Fans
integrated
to
alternating
modules

support
the
absorption
of
polluted
air.
56

55

Image
source
“Rennselear
SOA”
site,
http://www.rpi.edu/research/magazine/fall10/index.html.

56

“University
of
Toronto”
site,
15
January,
2011.
http://rad.daniels.utoronto.ca/2011/01/filtration-‐block/.

51

Figure
2-‐8:
Filtration
Block
57

2.8.3
“Bubble
Wrap”
by
Andrew
TÉTRAULT
/
Ben
LEE:
An
air-‐purifying

infrastructure
for
New
York
City.

An
exterior
application
of
the
phytoremediation
process
is
proposed
in
this
project

(figure
2-‐9).
It
is
an
air
purification
infrastructure,
inspired
by
the
“Andrea
ST

Filter”.
The
way
this
system
operates
is
that
it
collects
air
form
subway
exhausts
via

an
extensive
chimney
system.
The
air
is
being
filtered
through
consecutive
planted

“pods”
and
is
then
being
re-‐released
into
street
level.
These
pods
work
are
also
used

as
a
public
outdoor
space.
58

57

Image
source
“Pinterest”
site,
http://images.wantmi.com/wp-‐content/uploads/2012/08/Filtration-‐Block-‐
Elaine-‐Tong-‐3.jpg.

58

“Sucker
Punch
Daily”
site,
http://www.suckerpunchdaily.com/2011/04/10/bubble-‐wrap/#more-‐13010.

52

Figure
2-‐9:
"Bubble
Wrap"
59

Even
though
these
studies
introduce
the
phytoremediation
processes
in

architecture
and
propose
some
very
interesting
applications
there
are
no
data

available
on
their
effectiveness.
Therefore,
it
is
uncertain
whether
these
designs

have
any
actual
filtration
properties
or
are
based
solely
on
studies
conducted
for

environmental
purposes.

59

Image
source
“Sucker
Punch
Daily”
site,
http://www.suckerpunchdaily.com/2011/04/10/bubble-‐
wrap/#more-‐13010.

53

2.9
CONCLUSIONS

Air
filtration
is
a
method
that
needs
to
take
into
account
many
parameters
in
order

to
have
effective
results
in
ensuring
air
quality
for
maintaining
human
life
quality

and
comfort
within
the
established
standards,
but
more
importantly
to
prevent

serious
health
issues
that
may
occur
when
these
standards
are
not
being
followed.

With
the
evolution
of
science,
new
methods
are
being
proposed
as
filtration

methods,
more
sustainable
and
environmental
friendly.
The
following
chapters
will

investigate
the
possibility
of
utilizing
these
methods,
and
more
specifically

phytoremediation,
as
an
alternative
filtration
medium.

54

Chapter
Three:
Methodology

This
chapter
will
examine
the
effectiveness
of
a
system
using
the
dry
deposition
and

phytofiltration
process
in
order
to
treat
airborne
fine
Particulate
Matter.

Since

software
that
will
allow
the
simulation
of
such
a
procedure
does
not
exist
yet,
the

simulation
was
needed
to
done
through
a
physical
model.

In
this
chapter
the

methodology
of
setting
up
the
experiment
is
described.

3.1
PARTICULATE
MATTER
2.5

The
pollutant
that
the
system
was
tested
to
determine
its
filtration
possibilities
was

PM2.5.
As
it
was
noticed
from
the
data
taken
from
AQMD,
PM2.5
often
presents
high

concentrations
in
the
ambient
air
of
the
Central
Los
Angeles
area
and
it
is
often
a

reason
that
the
Air
Quality
Index
decreases
from
good
to
moderate.
Furthermore,

the
24-‐hour
average
has
exceeded
the
NAAQS
in
a
total
of
17
times
in
the
period
of

five
months,
more
times
than
allowed
per
year
(Figure
3-‐1).
The
data
were
taken

from
the
AQMD
and
the
hourly
values
for
each
day
were
averaged
to
get
the
24-‐hour

average.

55

Figure
3-‐1:
Daily
24-‐hr
average
and
Maximum
Value
of
PM2.5
for
Central
Los
Angeles,
from
1st
of

October
to
21st
of
March

Particulate
Matter,
especially
PM2.5
is
one
of
pollutants
that
pose
a
big
threat
in

human
health,
as
fine
dust
can
reach
the
lungs
through
inhalation
and
is
responsible

for
a
lot
of
health
problems
inhabitants
of
big
cities
face.
Particulate
Matter
is
a

pollutant
that
can
be
found
both
in
the
indoor
air
as
well
as
the
ambient
air.
This

pollutant
has
also
serious
health
impacts
in
human
health.
This
study
focuses
in

capturing
fine
Particulate
Matter
from
ambient
air
and
introducing
it
in
interior

spaces
for
improving
IAQ.

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

µg/m3

PM2.5
Daily
High
and
24hr
average

NAAQS
24hr
average
24hr
average
Max
Value

56

3.2
SYSTEM
DESCRIPTION
AND
INTEGRATION
SCHEMES

The
airflow
patterns
in
urban
built
environments
were
examined
in
order
to

understand
how
Particulate
Matter
may
move
in
an
urban
street
canyon,
and

determine
what
configuration
and
which
surfaces
would
be
appropriate
for
the

system
to
be
applied
on.
The
suggested
possible
configurations
of
the
system,
taking

advantage
of
the
entire
building
envelope
are
shown
in
the
following
diagrams.

3.2.1
Vertical
Configuration

Configuration
as
a
vertical
vegetated
surface
(Figures
3-‐2,
3-‐3).
This

configuration
will
be
that
of
a
vegetated
façade,
parallel
to
the
existing
façade
of
the

building.
It
may
be
as
a
living
wall
or
a
screen.
In
both
configurations
the
air
may

enter
the
interior
of
the
building
through
ducts,
or
through
natural
ventilation.

Figure
3-‐2:
Vertical
(Screen)
Configuration

57

Figure
3-‐3:
Vertical
(Living
Wall)
Configuration

3.2.2
Shelves
Configuration

Configuration
as
shelves
on
the
exterior
of
the
façade
(Figure
3-‐4).
This

configuration
will
be
that
of
a
vertical
green
house,
where
shelves
with
the
plants

will
be
placed
perpendicular
to
the
existing
façade.
It
may
be
as
a
part
of
a
double

skin
façade.
The
filtration
of
the
air
will
be
happening
through
dry
deposition
and

phytofiltration.
The
air
may
enter
the
interior
of
the
building
through
ducts,
or

through
natural
ventilation.

58

Figure
3-‐4:
Shelves
Configuration

3.2.3
Horizontal
Configuration

Configuration
as
a
horizontal
surface
(Figure
3-‐5).
This
configuration
will
be
that

of
a
green
roof
with
an
agricultural
membrane
placed
above
it,
or
a
short

greenhouse.
With
this
configuration
the
system
can
only
be
applied
on
the
roof
of

the
building.
The
air
filtered
will
be
that
at
the
roof
level,
so
it
will
mostly
be
an
air

filtration
method
for
the
ambient
air,
however
ducts
may
be
used
to
bring
the

filtered
air
in
the
interior
of
the
building.

59

Figure
3-‐5:
Horizontal
(Green
Roof)
Configuration

3.3
THE
ENVIRONMENTAL
CHAMBER

Since
computer
software
that
will
allow
modeling
the
suggested
system
does
not

exist,
an
environmental
chamber
was
built
to
measure
the
efficiency
of
the
method

proposed.

The
environmental
chamber
configuration
was
based
on
the
method

used
to
test
conventional
filters.

The
process
consists
of
a
source
that
will
supply

the
system
with
an
amount
of
particles.
These
particles
are
be
pushed
through
the

filter
by
a
fan.
The
filtration
efficiency
is
measured
by
two
sensors,
one
measuring

the
concentration
in
µg/m
3

at
the
inlet
(upstream
particles)
and
one
measuring
the

concentration
of
particles
at
the
outlet
(downstream
particles).
The
filter,
in
this

case
the
vegetated
surface,
will
be
placed
in-‐between
the
two
sensors.
The
process

is
summarized
in
the
following
diagram
(figure
3-‐6).

60

Figure
3-‐6:
Environmental
Chamber
Basic
Configuration

The
following
materials
and
parts
were
used
to
build
the
environmental
chamber:

-‐ Vertical
sides
of
the
chamber:
Four
pieces
of
Plexiglas
with
dimensions

18”x36”
and
18”x18”
of
0.22
inch
thickness.
One
hole
at
each
of
the

18”x18”
sides
were
drilled
in
the
center
and
12”
from
the
bottom
to

mount
the
vents.
The
pieces
were
glued
together
with
a
special
adhesive

to
prevent
air
leakages.
Plexiglas
was
chosen
as
material
that
allows

immediate
viewing
at
the
interior
of
the
chamber.

-‐ Lid:
Plexiglas
surface
with
dimensions
18”x36”
of
0.22
inch
thickness.
At

the
edges
of
this
piece,
rubber
foam
weather
seal
was
added
to
prevent

air
leaking.

-‐ Plywood
base:
The
base
was
constructed
by
18”x36”
plywood
of
¾”

thickness.
At
the
bottom
poplar
square
wood
dowels
of
1”
thickness
were

added
to
prevent
warping
of
the
base.
The
Plexiglas
pieces
were
then

drilled
on
the
base
with
screws
with
seals
and
the
joints
were
covered

with
silicon
to
prevent
leaking.

-‐ Adjustable
Bottom:
A
second
base
that
would
allow
adjusting
the
height

that
the
plants
were
located
was
also
necessary.
This
base
was
also

Particle

source

fan

Sensor

(measuring

upstream

particles)

Filter

(plants)

Sensor

(measuring

downstream

particles)

61

constructed
by
plywood
of
½”
thickness.
At
the
bottom
square
wood

dowels
of
1”
thickness
were
added
to
prevent
warping.
Round
wooden

dowels
of
different
height
were
used
to
adjust
its
height.
This
base
also

needed
to
be
sealed
to
avoid
leaking.
Clear
plastic
weather
seal
strip
was

used
to
avoid
leaking
of
air
to
the
below
compartment.

-‐ Vents:
Two
4-‐inch
diameter
plastic
vents.
(SM-‐RSV-‐4).

-‐ Sensor
Cases:
Two
4-‐inch
coupling
PVC
pipes
(HubxHub)

-‐ Flexible
Vinyl
Duct.
To
connect
the
PVC
pipes
with
the
fan
and
the

provision
of
the
particle
material.

-‐ Fan:
An
Altwood
Turbo
4000
fan
was
used.
The
fans
speed
was
not

adjustable
so
it
was
connected
to
an
electronic
step-‐less
speed
control
in

order
to
change
the
air
velocity
in
the
chamber.

The
environmental
chamber
was
designed
to
work
as
follows:
The
air
would
be

pushed
through
the
leaves
of
the
plants
to
examine
and
evaluate
the
process
of
dry

deposition
and
phytofiltration.
Two
sensors
one
at
the
inlet
and
one
at
the
outlet

where
placed
to
measure
the
amount
of
airborne
particulate
matter
at
these

locations.
The
difference
between
these
two
values
determines
the
effectiveness
of

the
process
as
a
filtering
method.
This
way
the
amount
of
particles
deposited

directly
on
the
leaves
of
the
plants
can
be
quantified.
It
can
be
assumed
that
most
of

these
particles
will
be
absorbed
by
the
stomata
of
the
leaves
and
broken
down

through
the
plant
metabolism.

62

Figure
3-‐7:
Environmental
Chamber
Diagram

3.3.1
Plant
selection

The
plant
species
selection
was
a
very
important
parameter
for
this
study,
as
it

should
be
a
plant
that
would
be
able
to
grow
under
specific
conditions,
tolerate
air

pollution
and
have
specific
foliage
geometry.
In
order
for
the
plant
to
be
able
to
be

used
with
the
architectural
configurations
mentioned
above
it
should
be
an

herbaceous,
perennial
plant.
To
add
to
that
the
species
should
be
able
to
survive

long
exposure
in
sunlight,
not
having
a
lot
of
maintenance
needs
–
especially

watering
–
and
be
tolerant
to
air
pollution.
The
plant
selected
was
“Festuca
Festina”

(blue
fescue).
The
selection
was
done
based
on
the
following
factors:

-‐ Foliage
type
(figure
3-‐8)
According
to
the
boards
provided
by
the
research

mentioned
earlier
conducted
by
the
Central
Pollution
Control
Board
of
Delhi,

pine
tree
has
a
good
dust
deposition
capability.
As
the
dust
deposition
is

mainly
affected
by
the
morphology
of
the
plant
leaves,
a
plant
with
similar

type
of
foliage
needed
to
be
found.
The
foliage
of
the
pine
tree
consists
of

63

needle
shaped
leaves
bundled
in
clusters
called
fascicles.
60

Similarly
the

foliage
of
fescue
is
made
from
waxy
blades
that
will
encourage
the
dust

deposition
on
their
surface.
Furthermore,
its
surface
is
ridged
which

increases
its
dust
capturing
possibilities.
Another
important
aspect
of
the

foliage
will
be
the
stomata
configuration
that
determined
the
amount
of
the

pollutants
the
plant
can
uptake
and
break
through
its
metabolism.

Figure
3-‐8:
Fescue
Ridged
Leaf
Surface
61

-‐ Root
configuration
(figure
3-‐9).
For
the
purposes
of
the
architectural

application
on
the
vegetated
surface
the
root
system
should
be
shallow
so
it

can
allow
the
plant
to
grow
on
shallow
substrates
that
are
used
on
living
wall

or
green
roof
configurations.
The
species
belongs
in
the
grasses
categories

that
have
shallow
roots
that
make
it
ideal
for
growing
on
a
shallow
substrate.

60

“Wikipedia”
site,
last
modified
on
26
March
2013,
http://en.wikipedia.org/wiki/Pine.

61

Image
source
“Oregon
State
University”
site,
http://horticulture.oregonstate.edu/node/592.

64

Figure
3-‐9:
Fescue
Root
System
62

-‐ Growing
conditions
(figure
3-‐10).
The
plant
selected
grows
to
a
maximum

height
of
18
inches
and
its
maximum
spread
is
also
18
inches.
Its
life

expectancy
is
about
8
years
when
it
is
properly
maintained
and
in

appropriate
environmental
conditions.
It
is
a
plant
that
can
survive
sun

exposure
and
actually
it
benefits
from
full
sun
or
partial
shade.
It
grows

mainly
in
average
to
dry
locations
and
dislikes
excessive
moisture.
It
is

considered
as
a
drought-‐tolerant
plant
and
it
makes
a
good
choice
for

xeriscape
applications.
63

62

Image
source
“eHow”
site,

http://www.ehow.com/how_7188532_grow-‐blue-‐fescue-‐seed.html

63

“Squak
MT,
Greenhouse
and
Nursery”
site,

http://www.qscaping.com/12230001/Plant/6441/Festina_Blue_Fescue

65

Figure
3-‐10:
Growing
Properties
according
to
the
seller
tag.

“Festina
Festuca”
was
found
appropriate
for
using,
as
it
fulfills
the
factors
discussed

for
the
species
selection,
plus
it
is
a
native
California
species,
which
is
one
more

advantage
for
selecting
it.

3.4
ENVIRONMENTAL
CHAMBER
FINAL
SETUP

Two
different
setups
were
used
before
concluding
what
the
best
setup
would
be
for

the
purposes
of
this
study.
The
previous
configurations
are
described
in
Appendix
A,

along
with
the
results
of
the
measurements
realized
and
the
problems
that

occurred.
To
summarize,
once
the
initial
setup
was
tested
the
limitations
that

occurred
were
taken
into
consideration.
The
Aerosol
Lab
of
the
USC
Viterbi
School

of
Civil
and
Environmental
Engineering
was
then
advised,
to
determine
the
best

solution
for
the
problems
encountered
and
to
acquire
access
to
more
accurate

documentation
equipment.
The
two
most
important
parameters
that
needed
to
be

controlled
were
the
stability
of
the
concentration
of
the
sample
of
particles

66

introduced
inside
the
chamber
and
the
issue
of
leaking
which
could
not
be
fully

controlled.

The
final
set
up
of
the
environmental
chamber
used
for
the

measurements
is
illustrated
at
the
figure
below
(Figure
3-‐11).

Figure
3-‐11:
Environmental
Chamber
final
setup

The
chamber
was
then
transferred
at
the
off-‐campus
Aerosol
lab
to
perform
the

measurements.
This
would
provide
a
solution
for
both
of
the
parameters
mentioned

above.
First,
for
the
particles
introduced
into
the
chamber
ambient
air
was
used.

That
would
ensure
both
a
steady
and
continuous
concentration
of
particles,
but
it

would
also
provide
more
realistic
results,
as
real
world
conditions
were
used.

Second,
the
leaking
of
the
chambers
was
a
given
and
despite
the
efforts
to
make
the

chambers
airtight,
it
was
a
problem
that
could
not
be
surpassed.
Placing
the

chamber
outdoors
ensured
that
the
air
infiltrating
the
chamber
would
have
the

same
particle
concentration
as
the
air
used
to
perform
the
measurements.

Therefore,
air
infiltrating
would
not
result
as
decreasing
the
concentration

measured
at
the
outlet
due
to
dilution.

67

3.4.1
Instruments
Used
for
the
final
setup

The
chamber
was
then
connected
to
more
accurate
instruments,
compared
to
the

sensors
used
during
the
initial
setup,
to
perform
the
tests.
These
were
the
following:

-‐ TSI
DustTrak
8520
Aerosol
Monitor:
These
sensors,
according
to
the

specification
sheets,
are
able
to
monitor
particle
sizes
ranging
from
PM1.0,

PM2.5
and
PM10.
They
have
a
continuous
analog
output
that
displays
the

particle
mass
concentration
in
mg/m
3
.
The
DustTrak
sensors
provide
a
real-‐
time
measurement
based
on
90
o

scattering.
A
pump
draws
the
sample
aerosol

through
an
optics
chamber
were
it
is
measured.
64

-‐ TSI
3022A
Ultrafine
Condensation
Particle
Counter:
The
Condensation

Particle
Counter
is
an
instrument
able
to
measure
the
number
of
particles

from
7nm
up
to
more
than
3μm.
The
output
is
displayed
on
an
LED
screen

and
expressed
as
0.00*10
n

particles/cm
3
.
It
can
count
particle
concentration

up
to
10
7

and,
according
to
the
specification
sheet
it
has
a
false
background

count
less
than
0.01
particle/cm
3
.

-‐ TSI
3080
Electrostatic
Classifier:
This
instrument
was
used
to
measure
the

size
distribution
of
particles.
According
to
the
specification
sheet,
the
way
it

does
that
is
by
charging
specific
size
particles
either
with
a
positive,
negative

or
neutral
charge.
The
particles
than
enter
a
Differential
Mobility
Analyzer

(DMA)
and
are
separated
accordingly
to
their
electrical
charge.
Particles
with

64

TSI
DustTrak
specification
sheet:

http://www.tsi.com/uploadedFiles/_Site_Root/Products/Literature/Spec_Sheets/2980077_DustTrak_8520.pdf

68

a
negative
charge
are
repelled
and
deposited
on
the
walls,
particles
with

neutral
charge
exit
with
the
excess
air.
Only
particles
with
a
narrow
range
of

electrical
mobility
have
the
correct
trajectory
to
pass
through
an
open
slit
near

the
DMA.
65

3.4.2
Plants
configurations
inside
the
chamber

The
configuration
of
the
plants
inside
the
chamber
was
also
an
important
parameter

for
the
testing.
Several
different
configurations
were
tested
that
represented

different
conditions
of
the
area
and
placement
of
a
vegetated
surface
applied
on
the

building
envelope.
These
configurations
would
also
help
to
understand
the
potential

relationship
between
the
area
and
volume
of
the
vegetation
to
the
possible
filtration

of
particles.
By
gradually
increasing
the
area
that
the
plants
would
cover
the
results

could
be
better
extrapolated
for
bigger
surfaces.
The
following
diagrams
illustrate

the
different
positioning
configurations
of
the
pots
of
the
plants
in
the
chamber,
as
a

plan.

Figure
3-‐12:
Two
plants
at
the
sides
of
the
chamber,
total
area
of
vegetation
0.22ft
2
.

65

TSI
3080
Electrostatic
Classifier
specification
sheet:

http://www.tsi.com/uploadedFiles/_Site_Root/Products/Literature/Spec_Sheets/3080.pdf

69

Figure
3-‐13:
One
row
of
plants,
total
area
of
vegetation
0.5
ft
2
.

Figure
3-‐14:
Two
rows
of
plants,
total
area
of
vegetation
1ft
2
.

Figure
3-‐15:
Three
rows
of
plants,
total
area
of
vegetation
1.5ft
2
.

70

Figure
3-‐16:
Five
rows
of
plants,
total
area
of
vegetation
2.5ft
2
.

Figure
3-‐17:
Two
rows
of
plants
at
the
sides,
total
area
of
vegetation
2ft
2
.

Figure
3-‐18:
Chamber
full
of
plants,
total
area
of
vegetation
4.5ft
2
.

71

3.4.3
Images
of
the
final
setup

Images
from
the
final
set
up
and
instruments.

Figure
3-‐19:

Final
setup
of
the
environmental
chamber,
inlet

72

Figure
3-‐20:
Final
setup
of
the
environmental
chamber,
outlet
and
pump

Figure
3-‐21:
The
DustTrak
Aerosol
Monitors

73

Figure
3-‐22:
The
DustTrak
Aerosol
Monitors
and
the
TSI
Particle
Counter

Figure
3-‐23:
The
TSI
Electrostatic
Classifier

74

3.5
TESTING
PROCEDURE

The
procedure
of
the
testing
was
straightforward
for
this
set-‐up.
A
pump
was

connected
at
the
outlet
to
pull
ambient
air
through
the
chamber.
One
aerosol

monitor
was
connected
to
the
outlet
to
measure
the
particle
mass
concentration

after
passing
through
the
chamber.
The
other
aerosol
monitor
was
measuring
the

mass
concentration
of
the
ambient
air.
The
particle
counter
was
alternately
either

measuring
the
particle
number
of
the
ambient
air
or
the
outlet
of
the
chamber.
The

same
was
done
with
the
Electrostatic
Classifier
for
the
ambient
air
and
the
chamber

full
of
plants.
The
readings
were
recorded
as
soon
as
the
indications
of
aerosol

sensor
and
the
particle
counter
connected
to
the
outlet
were
stabilized,
with
a

deviation
of
no
more
than
0.1
pc/cm
3

for
number
concentration
and
0.002
mg/m
3

for
mass
concentration
and
no
further
significant
change
occurred.
The
volumetric

flow
rate
that
the
pump
was
pulling
the
ambient
air
though
the
chamber
was
set
at

50lt/m.

75

Chapter
Four:
Data

The
experimental
process
developed
intended
to
investigate
if
a
vegetated
façade

could
substitute
a
conventional
air-‐filtration
system
to
improve
indoor
air
quality.

In
this
chapter
the
results
of
the
experiments
performed
are
presented
for
each
of

the
different
configurations
of
the
plants
inside.
These
configurations
aimed
to

address
the
following
questions
relevant
to
the
study
and
the
application
of
a

vegetated
surface
on
the
building
envelope:

-‐ The
maximum
possible
efficiency
that
can
be
achieved
with
the
specific

setup.
The
most
substantial
question
of
this
study
was
whether
there
would

be
any
noticeable
particle
removal
by
the
vegetated
surface,
compared
to
the

control
measurement.

-‐ The
relevance
between
the
vegetated
surface
area
and
the
filtration

efficiency.
By
gradually
increasing
the
amount
of
the
vegetated
surface
inside

the
chamber,
the
efficacy
of
the
vegetation
per
unit
area
was
investigated
and

then,
it
was
attempted
to
be
expressed
in
the
form
of
a
useful
metric

(percentile
for
surface
area).

-‐ The
configuration
of
plants
inside
the
chamber
also
reflected
different

applications
of
vegetated
facades
to
examine
their
potential
efficiency.
A

screen
configuration,
with
or
without
an
opening,
was
represented
by
one

row
of
plants
in
front
of
the
outlet.

76

-‐ The
effect
of
wet
foliage
was
also
tested
to
investigate
whether
wet

deposition
of
particles
would
be
a
more
or
less
effective
mechanism
for

phytofiltration.

The
data
acquired
from
the
experiments
present
the
percentile
of
the
particle

number
reduction
and
the
mass
concentration
for
each
test.
The
tests
were

performed
at
the
off-‐campus
Aerosol
Lab
of
the
Viterbi
School
of
Environmental
and

Civil
Engineering.
The
map
below
shows
the
location
of
the
off-‐campus
lab
(Figures

4-‐1,
4-‐2).

Figure
4-‐1:
Location
of
the
off-‐campus
Aerosol
lab

77

Figure
4-‐2:
Location
of
the
off-‐campus
Aerosol
lab
and
proximity
to
110
Freeway

The
off-‐campus
lab
is
located
at
a
parking
lot,
close
to
the
110
Harbor
Freeway
and

was
an
ideal
location
for
running
the
measurements,
as
the
concentration
of
PM2.5

would
be
increased
due
to
the
traffic
on
the
freeway.

4.1
AMBIENT
AIR
CONDITIONS
ON
THE
DAY
OF
THE
EXPERIMENT
AND

ADITIONS
TO
THE
SET-‐UP

To
address
the
limitation
of
air
infiltration
that
occurred
during
the
experiments

performed
in
lab
environment
and
led
to
significantly
decreased
measurements
at

the
outlet,
the
chamber
was
transferred
outdoors.
This
would
ensure
that
the

composition
of
the
air
infiltrating
would
be
the
same
as
the
composition
of
air
used

to
take
the
measurements.
Ambient
air
was
used
to
examine
if
particle

concentration
could
be
reduced
by
the
vegetated
surface.
It
is
important
to
describe

78

the
ambient
air
particulate
matter
levels
for
the
specific
day.
The
measured
PM2.5

for
that
day,
during
the
hours
that
the
experiment
took
place
was
15.0,
18.0,
21.0,

34.0
μg/m
3

for
12:00am
to
3:00am
respectively,
according
to
data
taken
from
the

AQMD,
for
the
Central
Los
Angeles
area.
However,
the
recorded
ambient
mass

concentration
of
the
particles
during
the
experiment
differs
from
these
numbers.

More
specifically,
the
total
mass
concentration
of
Particulate
Matter
recorded

during
the
experiments
is
much
higher
than
the
reported
AQMD
mass
concentration

of
PM2.5.
This
can
be
justified
for
two
reasons.

First,
the
air
quality
measurements

are
taken
at
least
one
level
above
ground,
while
the
experiment
measurements
were

done
on
ground
level,
where
the
mass
concentration
of
particles
is
much
higher
due

to
immediate
exposure
to
traffic
pollution,
soil
dust
and
other
types
of
dust
that
do

not
reach
the
higher
levels
of
air.
The
second
reason
is
that
the
DustTrakt
Aerosol

Monitor
sensors
used
for
the
experiment,
are
not
able
to
distinguish
between

particle
sizes
and
in
addition
they
take
into
account
particles
with
mass
even
higher

than
10μm.
The
particle
mass
concentration
reported
is
the
total
amount
of
mass
for

the
entire
range
of
airborne
particles
that
starts
from
approximately
0.1μm
and
goes

up
to
10μm
or
more.
Therefore,
airborne
particles
that
are
not
in
the
area
of
the

interest
of
this
study,
above
2.5μm,
are
included
in
the
reading
of
the
sensors.

To
address
this
limitation
of
the
sensors,
another
instrument
was
added
into
the

setup
that
would
be
able
report
the
amount
of
airborne
particles.
The
TSI

Condensation
Particle
Counter
reported
the
number
of
particles
per
cm
3

at
single

data
point.
This
instrument
was
then
connected
to
the
TSI
Electrostatic
Classifier

79

that
provided
a
sample
analysis
and
a
plot
of
the
size
distribution
of
particles
in

ambient
air.
This
way,
the
reduction
of
the
actual
number
of
particles
could
be

measured
and
with
the
addition
of
the
size
distribution
plot,
the
specific
sizes
of
the

particles
removed
by
the
plants
could
be
determined.
The
pump
connected
to
the

chamber
was
set
to
pull
the
air
at
50lt/m,
but
due
to
infiltration
the
flow
rate
could

not
be
considered
consistent
throughout
the
volume
of
the
chamber.
The
measured

flow
rate
at
the
inlet
was
less
than
10lt/m.

4.1
EXPERIMENT
RESULTS

The
following
tables
illustrate
the
reduction
of
the
particle
amount
as
well
as
the

concentration
of
ambient
air
compared
to
the
mass
concentration
of
particles
inside

the
chamber.
The
reduction
for
both
of
these
values
is
expressed
as
a
percentile.
The

values
of
the
number
concentration
where
taken
when
the
instruments
indication

was
stabilized
around
a
specific
number
with
a
0.1
positive
or
negative
deviation
for

the
particle
number
concentration
and
0.002
positive
or
negative
deviation
for
the

mass
concentration.
Those
values
were
documented
and
then
averaged
to
get
the

average
number
and
mass
concentration.

4.1.1
Control
Measurement,
Empty
Chamber

A
control
measurement
was
important,
as
it
would
indicate
if
any
changes
in
the

number
or
mass
concentration
would
be
due
to
the
chamber,
and
if
so
in
what

amount
did
the
chamber
contribute
to
the
reduction
of
particles.

80

Figure
4-‐3:
Control
Measurement,
empty
chamber

Table
4-‐1:
Control
Measurement
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
3.72
*10
4

37200

37883
0.056

3.83
*10
4

38300

3.79
*10
4

37900

3.90
*10
4

39000

3.68
*10
4

36800

3.81
*10
4

38100

Chamber
3.04
*10
4

30400
29883
0.034

3.01
*10
4

30100

2.95
*10
4

29500

3.10
*10
4

31000

2.93
*10
4

29300

2.90
*10
4

29000

PERCENTILE

21.12%
39.29%

The
control
measurement
was
performed
two
times
and
indicated
that
there
was
an

average
19.48%
decrease
of
the
number
concentration
of
particles
and
an
average

37%
reduction
of
mass
concentration.
A
difference
of
more
than
5%
for
the

measurements
following
would
indicate
a
filtration
possibility,
as
a
difference
less

81

than
that
may
be
due
to
the
fluctuation
of
the
levels
of
particulate
matter
in
the
air

rather
than
the
presence
of
plants
inside
the
chamber.

4.1.2
Plants
at
the
sides
of
the
outlet

Figure
4-‐4:
Configuration
1,
two
plants
at
the
sides

Table
4-‐2:
Two
plants
at
the
sides
of
the
outlet,
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
2.38
*10
4

23800

23650
0.084

2.30
*10
4

23000

2.43
*10
4

24300

2.35
*10
4

23500

Chamber
2.00
*10
4

20000

19650
0.055

1.91
*10
4

19100

1.96
*10
4

19600

1.99
*10
4

19900

PERCENTILE

16.91%
34.52%

This
setup,
which
was
representing
a
screen
configuration
with
an
opening
in
front

of
the
outlet,
did
not
show
any
improvement
compared
to
the
control
measurement.

82

4.1.3
Plants
at
the
sides
of
chamber

The
following
setup
was
a
hyperbolic
configuration
of
the
previous.
This

configuration
aimed
to
determine
whether
the
biggest
amount
of
vegetation
that

was
possible
to
be
placed
inside
the
chamber
without
having
any
plants
directly
in

front
of
the
outlet
would
provide
any
filtration.

Figure
4-‐5:
Configuration
5,
plants
at
sides
of
the
chamber

Table
2-‐3:
Plants
at
the
sides
of
the
chamber
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
2.30
*10
4

23000
23320
0.075

2.31
*10
4

23100

2.35
*10
4

23500

2.38
*10
4

23800

2.32
*10
4

23200

Chamber
1.59
*10
4

15900

15600
0.059

1.57
*10
4

15700

1.55
*10
4

15500

1.61
*10
4

16100

1.48
*10
4

14800

PERCENTILE

33.10%
21.33%

83

The
results
showed
a
slight
decrease
of
the
particle
number
concentration.

4.1.4
One
row
of
plants

Figure
4-‐6:
Configuration
2,
one
row
of
plants

Table
4-‐4:
One
row
of
plants
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
2.60
*10
4

26000
25300
0.083

2.54
*10
4

25400

2.45
*10
4

24500

Chamber
1.96
*10
4

19600
19200
0.060

1.88
*10
4

18800

1.92
*10
4

19200

PERCENTILE

24.11%
27.71%

This
measurement
that
was
representing
the
screen
configuration
showed
a
slight

improvement
compared
to
the
control
measurement.
This
application
appears
to

have
a
slight
potential
in
filtering
airborne
particles

The
purpose
of
the
following
configurations
was
to
determine
whether
increasing

the
amount
of
the
vegetated
surfaced
would
result
increased
filtration
efficiency.

84

4.1.5
Two
rows
of
plants

Figure
4-‐7:
Configuration
3,
two
rows
of
plants

Table
4-‐5:
Two
rows
of
plants
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
2.67
*10
4

26700

26620
0.082

2.59
*10
4

25900

2.62
*10
4

26200

2.78
*10
4

27800

2.65
*10
4

26500

Chamber
1.74
*10
4

17400
18020
0.0575

1.80
*10
4

18000

1.79
*10
4

17900

1.87
*10
4

18700

1.81
*10
4

18100

PERCENTILE

32.31%
29.88%

85

By
doubling
the
amount
of
vegetation
inside
the
chamber
the
efficiency
of
the

system
increased
noticeably.
The
measurement
showed
a
32.31%
in
reducing
the

particle
number
concentration
compared
to
the
ambient
air.

4.1.6
Three
rows
of
plants

Figure
4-‐8:
Configuration
4,
three
rows
of
plants

Table
4-‐6:
Three
rows
of
plants
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
2.71
*10
4

27100

26920
0.082

2.66
*10
4

26600

2.68
*10
4

26800

2.67
*10
4

26700

2.74
*10
4

27400

Chamber
1.70
*10
4

17000
16380
0.056

1.66
*10
4

16600

1.63
*10
4

16300

1.61
*10
4

16100

1.59
*10
4

15900

PERCENTILE

39.15%
31.71%

86

4.1.7
Five
Rows
of
plants

Figure
4-‐9:
Configuration
6,
five
rows
of
plants

Table
4-‐7:
Five
rows
of
plants
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
2.28
*10
4

22800
23546
0.076

2.34
*10
4

23400

2.35
*10
4

23530

2.38
*10
4

23800

2.42
*10
4

24200

Chamber
1.48
*10
4

14800

14980
0.045

1.55
*10
4

15500

1.49
*10
4

14900

1.50
*10
4

15000

1.47
*10
4

14700

PERCENTILE

36.38%
40.79%

87

4.1.8
Chamber
full
of
plants
(8
rows)

Figure
4-‐10:
Configuration
7,
eight
rows
of
plants,
full
chamber

Table
4-‐8:
Eight
rows
of
plants
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
2.58
*10
4

25800
25460
0.073

2.51
*10
4

25100

2.56
*10
4

25600

2.50
*10
4

25000

2.58
*10
4

25800

Chamber
1.38
*10
4

13800

13580
0.055

1.37
*10
4

13700

1.35
*10
4

13500

1.36
*10
4

13600

1.33
*10
4

13300

PERCENTILE

46.66%
24.66%

This
measurement
was
performed
twice
and
showed
an
average
reduction
in
the

particle
number
concentration
of
51.28%
compared
to
ambient
air
and
it
was
the

best
efficiency
recorded.

88

Subsequently,
it
was
tested
whether
moisture
on
the
foliage
of
the
plants
would

affect
the
results,
for
two
of
the
above
configurations.

4.1.9
One
row
of
plants
with
wet
foliage

Figure
4-‐11:
Configuration
2,
one
row
of
plants,
wet
leaves

Table
3:
One
row
of
plants
Wet
Deposition
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
3.33
*10
4

33300

33680
0.061

3.40
*10
4

34000

3.35
*10
4

33500

3.39
*10
4

33900

3.37
*10
4

33700

Chamber
2.32
*10
4

23200

23540
0.038

2.36
*10
4

23600

2.40
*10
4

24000

2.38
*10
4

23800

2.31
*10
4

23100

PERCENTILE

30.11%
37.70%

89

This
measurement
showed
an
increase
in
the
efficiency,
compared
to
the
same

measurement
with
dry
foliage
of
about
6%.
This
is
not
a
significant
difference
to

make
safe
conclusions
about
the
effectiveness
of
wet
deposition.

4.1.10
Full
chamber,
wet
foliage

Figure
4-‐12:
Configuration
7,
eight
rows
of
plants,
wet
leaves

Table
4-‐10:
Eight
rows
of
plants
Wet
Deposition
Results

Particles/cm
3

Average
pc/cm
3

mg/m
3

Ambient
3.44
*10
4

34400
33450

0.057

3.37
*10
4

33700

3.22
*10
4

32200

3.24
*10
4

32400

3.39
*10
4

33900

3.41
*10
4

34100

Chamber
1.66
*10
4

16600
17225

0.056

1.76
*10
4

17600

1.70
*10
4

17000

1.72
*10
4

17200

1.79
*10
4

17850

1.71
*10
4

17100

PERCENTILE

48.51%
1.75%

90

The
measurement
did
not
show
any
increased
efficiency
compared
to
the

measurements
performed
with
dry
leaves.

4.1.11
Size
Distribution
Plot

By
observing
the
results
of
the
measurements
above,
it
was
noticed
that
the

readings
of
the
DustTrak
sensors
compared
to
the
Particle
Counter
were

contradicting.
While
the
dust
monitors
were
indicating
that
the
reduction
of
mass

concentration
remained
around
the
same
levels
for
all
of
the
measurements,
the

particle
counter
showed
a
noticeable
decrease
in
the
particle
number
concentration.

In
order
to
validate
which
of
the
two
instrument
readings
was
correct,
the

Electrostatic
Classifier
was
connected
to
the
outlet
of
the
full
chamber
to
determine

if
indeed
there
was
any
reduction
and
what
was
the
specific
size
of
particles
the

plants
were
able
to
remove.
This
plot
was
compared
to
the
ambient
air
plot.
The

results
of
the
two
plots
are
presented
below.

91

Figure
4-‐13:
Comparative
Size
Distribution
Plot

The
plot
showed
a
significant
reduction
of
particles
that
their
diameter
was
in
the

range
of
0.01μm
to
1μm.
The
total
number
concentration
for
the
particles
in
this
size

range
was
25,744
pc/cm
3

and
the
particle
number
concentration
after
the
air

passed
through
the
chamber
was
18,617
pc/cm
3
.
The
percentile
of
particle
removal

for
the
total
of
particles
of
the
specific
spectrum
was
27.68%.

0

100

200

300

400

500

600

10
100
1000

Number
Concentration
(#/cm
3
)

Particle
Diameter
(nm)

Size
Distribution
Plot

Ambient
After
Chamber

92

4.2
CONCLUSIONS

The
results
of
the
measurements
showed
that
with
the
specific
setup
of
the
chamber

and
with
the
specific
plants
the
number
concentration
of
particles
can
be
reduced

for
most
of
the
configurations
used.
The
particle
removal
was
found
to
be
relevant

to
the
vegetated
surface
area,
as
a
gradual
increase
of
efficiency
was
recorded
in

accordance
to
the
increase
of
plants
inside
the
chamber.
The
placement
of
the
plants

also
proved
to
be
relevant
to
the
filtration
efficiency.
For
achieving
noticeable

particle
removal,
plants
needed
to
be
placed
directly
in
front
of
the
outlet.
Lastly,

wet
deposition
did
not
have
a
positive
or
negative
effect
on
the
filtration
efficiency.

93

Chapter
Five:
Analysis

In
this
chapter,
the
results
of
the
experiments
will
be
analyzed.
This
study
was
based

on
observations
made
during
an
experimental
procedure
and
not
on
a
mathematical

model,
or
simulation
software.
It
is
a
preliminary
research
on
this
subject
that

leaves
a
lot
of
room
for
further
improvement
of
the
method
and
future
analysis.

The
objectives
of
the
analysis
are
to:

-‐ Examine
the
validity
of
the
measurements
and
explain
the
factors
that
could

be
affecting
them.

-‐ Explain
the
difference
between
mass
concentration
and
number

concentration
of
particles.
This
will
help
in
understanding
why
there
was
a

difference
in
these
values
during
the
experimental
process.

-‐ Explain
the
difference
in
the
mechanisms
that
resulted
in
particle
removal

according
to
their
size
categorization.

-‐ Provide
a
comparative
table
for
removal
efficiency
compared
to
the
ambient

air
as
well
as
the
control
measurement.

5.1
RESULTS
ACCURACY

The
problem
of
infiltration
was
not
resolved
for
this
setup.
An
effort
was
made
to

provide
the
best
possible
solution
for
achieving
results
that
would
better
reflect
the

potential
filtration
efficiency
of
the
testing
cell.
From
the
tests
performed
previously

in
lab
environment,
it
was
observed
that
the
particle
mass
concentration
difference

94

between
the
inlet
and
the
outlet
was
far
from
what
was
expected,
especially
when

the
control
measurements
were
performed.
This
was
due
to
the
extremely
clean
lab

air
infiltrating
the
chambers
and
reducing
the
total
particle
mass
concentration
as
it

was
getting
mixed
up
with
the
aerosol
sample.
For
avoiding
that
consequence,
it
was

decided
that
since
it
was
not
possible
to
completely
address
the
leaking
problem,
an

adequate
solution
would
be
to
make
sure
that
the
air
being
pulled
through
the

chamber
would
have
the
same
mass
concentration
as
the
air
infiltrating.
That
way,

the
measurement
results
might
also
not
be
as
accurate
as
anticipated,
but
still
they

would
be
a
more
acceptable
representation
of
the
effectiveness
of
the
system.
The

infiltration
in
this
case,
would
work
as
a
disadvantage
to
the
measurements,
not

favoring
the
system
by
showing
a
higher
effectiveness
than
it
might
actually
have.

Furthermore,
it
might
be
a
better
representation
of
the
real
world
problem
since

this
system
will
be
placed
on
the
exterior
of
the
building,
where
that
parameter

cannot
be
controlled.

5.2
PARTICLE
CATEGORIZATION

The
results
of
the
measurements
showed
that
the
number
concentration
of
particles

was
significantly
reduced
by
the
vegetated
surface,
compared
to
ambient
air.
More

specifically,
the
particles
removed
were
secondary
particles.
Airborne
particles
of

the
ambient
air
that
can
infiltrate
indoor
spaces
can
be
categorized
as
primary
and

secondary
according
to
their
size.
Secondary
particulate
matter
has
a
size
smaller

than
2.5μm
and
usually
less
than
1.0μm.
The
difference
between
primary
and

secondary
is
that
the
latter
is
deposited
on
surfaces
through
diffusional
loss
and
not

95

through
gravitational
loss.
Bigger
particles
may
be
deposited
on
the
leaves
of
the

plants,
or
other
surfaces,
simply
when
pulled
by
gravity.
The
smaller
particle
losses

are
mainly
due
to
diffusion.
This
is
the
process
by
which
aerosol
particles
move

randomly
due
to
collisions
with
gas
molecules.
Such
collisions
may
lead
to
further

collisions
with
either
obstacles
or
surfaces.
66

Furthermore,
particles
that
their
mass
is

bigger
are
usually
deposited
within
hours
due
to
gravity.
On
the
other
hand,

particles
that
are
smaller
in
size
and
therefore
their
mass
is
smaller,
stay
for
longer

in
the
air,
sometimes
for
weeks,
and
are
deposited
on
surfaces
usually
trough

precipitation
67
.
Therefore,
the
number
concentration
of
these
sizes
is
much
bigger

compared
to
larger
particles.
Particles
of
this
size
are
also
the
ones
that
are
more

toxic
for
humans,
as
their
main
source
is
gases
that
their
chemical
elements
are
still

coagulating,
until
they
reach
the
size
of
0.3μm.

5.3
MASS
CONCENTRATION
AND
NUMBER
CONCENTRATION

Mass
concentration
of
particles
and
the
number
concentration
of
particles
are
two

different
methods
of
expressing
the
amount
of
the
specific
pollutant
in
the
air.
Mass

concentration
of
particles
is
expressed
in
μg/m
3

or
mg/m
3
,

which
is
essentially

related
to
their
volume.
The
number
concentration
of
airborne
particles
is

expressed
as
particles/cm
3
,
which
is
the
absolute
number
of
particles
for
a
specific

volume.
As
the
size
of
particles
suspended
in
the
air
increases
their
mass
also

increases,
but
their
actual
number
remains
the
same.
An
example
for
this
is
that

66

“Wikipedia”
site,
last
modified
on
27
March
2013,
http://en.wikipedia.org/wiki/Deposition_(aerosol_physics).

67

Ibid.

96

when
comparing
one
particle
with
diameter
0.1μm
to
one
particle
with
diameter

10μm,
the
volume
of
the
latter
one
is
about
10,000
times
bigger
(figure
5-‐2).

Therefore,
larger
particles
can
influence
more
the
mass
concentration
as
it
is

immediately
relative
to
the
volume
of
particles.
The
sensors
used
throughout
the

experiment
are
dust
sensors,
which
are
able
to
accurately
measure
the
mass

concentration
of
airborne
particles,
but
they
cannot
make
a
distinction
between
the

different
sizes.
Furthermore,
these
sensors
also
measure
particles
with
a
diameter

much
bigger
than
2.5μm
and
even
larger
than
10μm,
which
was
not
in
the
scope
of

work
of
this
study.

The
charts
below
represent
a
typical
concentration
of
particles
in
the
ambient
air,
as

their
size
distribution
in
relation
to
their
number,
their
surface
area
and
volume

(Figure
5-‐1)
and
a
comparison
of
different
sizes
of
particles
(Figure
5-‐2).
The

highest
values
differ
depending
on
which
of
the
methods
mentioned
above
is
used

to
quantify
the
particle
concentration.
When
looking
at
the
mass
concentration,
the

biggest
impact
is
from
particles
with
diameter
from
0.1
μm
to
1
μm
and
from
2.5
μm

to
up
to
more
than
10μm.
While
looking
at
number
concentration,
the
peak
value
is

for
0.01
μm.
The
red
area
represents
the
range
of
particles
of
the
size
distribution

plot
taken
during
the
experiments.

97

Figure
5-‐1:
A
typical
ambient
particle
distribution
as
a
function
of
particle
size
expressed
by
particle

number,
surface
area,
and
volume.
The
latter
is
equivalent
to
a
mass
distribution
when
variation
in

particle
density
is
small.
Vertical
scaling
is
individual
to
each
panel
68

Figure
5-‐2:
Comparison
of
Particulate
Matter
Size
69

68

Heal,
Mathew
et
al.
2012.
“Particles,
air
quality,
policy
and
health”
Chem.
Soc.
Rev.,
Vol.41,
pp.
6606-‐6630.

69

Image
source
“Santa
Barbara
Air
Pollution
Control
District”
site,

http://www.sbcapcd.org/images/sbcapcdParticleSize600.jpg

98

For
the
purposes
of
this
study
the
reduction
of
the
mass
concentration
of
particles

was
not
taken
into
consideration,
as
there
was
not
significant
deviations
throughout

the
different
configurations
tested.
That
is
because
the
aerosol
monitors
used
to

measure
the
difference
were
not
calibrated
in
a
way
that
could
accurately
account

particles
of
specific
ranges.
The
measurements
of
the
TSI
Particle
Counter
proved
to

be
more
in
the
scope
of
work
of
this
study,
as
they
were
measuring
number
of

particles
and
those
included
particles
with
a
diameter
as
small
as
7nm.
This
study

intended
to
focus
in
PM2.5.
However,
the
percentile
of
the
reduction
of
particle
mass

concentration
is
also
mentioned,
as
it
is
an
additional
indication
that
the
particles

removed,
by
the
different
configurations
compared
to
the
control
measurements,

are
the
secondary
particles,
which
do
not
impact
mass
concentration.

5.4
RESULTS
ANALYSIS

The
results
of
the
measurements
are
examined
in
total
to
determine
their
overall

efficiency
and
the
possibility
of
an
architectural
application.

5.4.1
Control
Measurement

The
control
measurement
showed
that
even
with
an
empty
chamber
the
number

concentration
of
particles
was
reduced
by
an
average
19.48%.
This
is
concluded
by

the
recorded
reduction
of
both
mass
and
number
particle
concentration
and
it
is

due
to
deposition
of
particles,
both
gravitational
and
diffusional
on
the
various

surfaces
of
the
chamber.

99

5.4.2
Vegetation
at
the
sides
of
the
opening

The
placement
of
the
plants
proved
to
be
a
key
factor
of
the
filtration
potential
of

the
vegetated
surface.
When
plants
were
not
placed
directly
in
front
of
the
outlet
the

recorded
efficiency
per
surface
area
was
minimal
to
poor
comparing
to
the

corresponding
when
the
plants
were
also
placed
in
front
of
the
outlet.

5.4.3
Screen
Configuration

By
observing
the
results,
it
is
noticed
that
even
one
row
of
plants
in
front
of
the

outlet
can
reduce
an
amount
of
particles
from
entering
indoor
spaces.
The

improvement
was
about
30%,
compared
to
the
ambient
air
number
concentration,

and
5.75%
compared
to
the
control
measurement.

5.4.4
Maximum
Vegetated
Surface

The
maximum
vegetated
surface
tested
was
when
the
chamber
was
filled
with

plants.
The
total
surface
area
was
4.5ft
2

and
the
measurement
results
showed
an

average
51.28%
reduction
in
the
particle
number
concentration
and
a
39.49%

improvement
compared
to
the
control
measurement.

100

5.4.5
Area
to
removal
ratio

The
study
also
attempted
to
find
a
relationship
between
the
vegetated
surface
area

and
the
efficiency
of
removal.
The
chamber
dimensions
were
a
given,
so
by

gradually
increasing
the
vegetation
surface
inside
it
was
observed
that
the
removal

efficiency
was
also
improved.
By
examining
the
removal
rate
of
the
different

configurations
it
can
be
concluded
that
as
the
vegetated
area
increases,
the
removal

efficiency
also
increases.

This
is
an
indication
that
with
a
specific
area
of
vegetation,

higher
removal
may
be
achieved.
It
needs
to
be
highlighted
again
that
the
spectrum

of
particles
that
were
taken
into
consideration
for
calculating
the
reduction
number

concentration
range
from
3nm
and
up.

Figure
5-‐3:
Removal
Efficiency
Percentile
to
Vegetated
Surface
Area

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5

Surface
Area
(ft
2
)

Removal
Percentile
to

Surface
Area

REDUCTION
REDUCTION
WET
LEAVES

REDUCTION
SIDES
VEGETATION

Reduction
Trend

101

Finally,
it
must
be
noted
that
the
results
were
obtained
with
a
specific
volumetric

flow
rate.
The
pump
was
set
at
50lt/m,
which
means
that
the
air
velocity
at
the

outlet
was
0.10
m/s.
The
maximum
possible
air
velocity
in
the
chamber
can
be

calculated
as
0.012m/s
but
that
is
probably
not
the
case
as
due
to
infiltration
it
is

expected
that
it
would
be
even
lower.
This
limitation
did
not
allow
for
tests
to
be

performed
with
different
volumetric
flow
rates.
The
results
presented
above
are

relevant
to
the
specific
flow
rate
and
different
follow
rates
could
result
different

efficiency.

5.4.6
Wet
Deposition

Wet
deposition
was
also
decided
to
be
tested,
as
water
is
an
element
that
is
present

through
the
entire
life
cycle
of
plants
either
as
a
part
of
their
nutrition,
or
as
a
part
of

their
metabolism
process,
through
transpiration
as
water
vapor.
Furthermore,
the

system
will
be
constantly
exposed
to
weather
conditions.
It
is
therefore
inevitable

that
the
foliage
of
the
plants
will
be
at
some
point
wet.
For
determining
whether
the

wet
foliage
of
plants
would
impact
the
filtration
efficiency,
it
was
decided
that
the

two
configurations
that
should
be
tested
initially
would
be
the
more
and
the
least

efficient.
These
were
the
one
row
of
plants
and
the
chamber
full
of
plants.
If
a

significant
improvement
was
documented,
then
more
configurations
would
be

tested.
The
measurements
showed
that
there
was
no
important
difference
in
the

reduction
of
the
particle
number
concentration
when
the
foliage
of
the
plants
was

wet
compared
to
dry
leaves.
The
reduction
noticed,
for
both
of
the
configurations,

was
less
than
5%,
compared
to
the
ones
with
dry
leaves.
That
can
be
attributed
as

102

result
of
the
fluctuation
of
the
amount
pollutants
in
the
ambient
air
when
taking
the

measurements.
With
this
setup,
the
deviation
was
too
small
to
conclude
whether

wet
deposition
is
more
effective,
as
a
filtration
method.

5.5
COMPARATIVE
TABLE
OF
EFFICIENCY

The
results
displayed
above
show
the
removal
efficiency
compared
to
the
recorded

ambient
air
concentration.
However,
it
is
important
to
compare
these
results
also
to

the
base
case,
as
there
was
a
noticeable
reduction
of
number
concentration
during

those
measurements
and
a
part
of
the
particles
removed
for
all
configurations
might

be
attributed
to
that.
The
following
table
displays
the
efficiency
of
the
different

configurations
compared
both
to
ambient
air
and
the
control
measurement.

Table
5-‐1:
Comparative
Table
of
Efficiency
%
to
ambient
air
concentration
and
to
the
control

measurement

Configuration
Area
(ft
2
)
%
compared
to

Ambient
Air

%
compared
to

Control
Measurement

Base
Case

0
19.48%
0.00%

1
row
of
plants
0.5
24.11%
5.75%

2
rows
of
plants
1
32.31%
15.93%

3
rows
of
plants
1.5
39.15%
24.43%

5
rows
of
plants
2.5
36.38%
20.99%

8
rows
of
plants
4.5
51.28%
39.49%

2
pots
at
the
sides
0.22
16.91%
0.00%

16
pots
at
the
sides
2
33.10%
16.92%

103

5.6
SIZE
DISTRIBUTION
ANALYSIS

The
size
distribution
analysis
of
the
chamber
when
it
was
full
with
plants
was

accounting
for
particles
with
diameter
range
from
0.01μm
up
to
1μm.
The
percentile

of
particle
removal
for
these
sizes
was
27.68%,
comparing
to
ambient
air.
Taking

into
consideration
the
total
reduction
of
the
number
of
particles
when
the
chamber

was
full
that
was
in
an
average
51.28%
the
vegetated
surface
was
able
to
also

remove
successfully
particles
with
a
diameter
more
than
1μm
and
less
than
0.01μm.

The
lower
detection
limit
was
3nm.
It
can
be
assumed,
from
the
charts
above

showing
a
typical
size
distribution
of
particles
in
the
ambient
air,
that
since
larger

particles
with
a
diameter
of
0.1μm
to
10μm
do
not
seem
to
impact
the
number

concentration,
and
the
mass
concentration
remained
the
same,
comparing
to
the

base
case,
that
the
majority
of
particles
removed
belong
in
the
fine
Particulate

Matter.
The
efficiency
percentage
per
size
is
shown
in
the
chart
below
with
an

indication
of
which
size
and
above
MERV
filters
address
(figure
5-‐4).

104

Figure
5-‐4:
Removal
percentile
per
Particle
Size

The
removal
efficiency
per
size
appears
to
be
more
consistent
for
sizes
between

0.01μm
and
0.3μm
with
a
steady
rate
ranging
between
20%
and
40%.
For
particles

with
diameter
bigger
than
0.3μm
the
efficiency
becomes
more
irregular
and

fluctuates
from
0%
to
40%.

-‐80.00%

-‐60.00%

-‐40.00%

-‐20.00%

0.00%

20.00%

40.00%

60.00%

10
100
1000

Particle
Size
(nm)

removal
percentile
per
size

limitation
of
MERV

ilters
(0.3μm)

105

5.7
CONCLUSIONS

The
analysis
of
the
results
showed
that
there
was
a
noticeable
reduction
in
the

particle
number
concentration
as
air
was
treated
in
the
chamber,
and
that
this

reduction
is
relevant
to
the
vegetated
surface.
A
significant
amount
of
particles

removed
proved
to
be
in
the
range
of
the
scope
of
work
of
this
study.
There
is
still
a

lot
of
room
for
improvement
of
the
experimental
process,
which
would
help
in

repeating
the
measurements
and
validating
the
results,
but
this
is
an
expected

difficulty
when
developing
a
physical
testing
method.

106

Chapter
Six:
Conclusions

This
study
focused
on
determining
whether
a
vegetated
façade
can
function
as
a

filtration
medium,
especially
for
particles
with
a
diameter
less
than
2.5μm,
to

increase
indoor
air
quality.
The
conclusions
are
described
in
this
chapter.

6.1
THE
DESIGN
OF
EXPERIMENTAL
PROCESS

As
mentioned
above,
an
experimental
method
needed
to
be
developed
to
perform

the
required
measurements.
This
method
included
the
construction
of
an

environmental
chamber
that
would
be
able
to
control
various
parameters
that
are

present
in
the
real
world
and
focus
on
the
filtration
efficiency
of
the
specific

vegetated
area.
The
process
of
constructing
the
chamber
itself
was
challenging,
as

there
were
many
issues
that
needed
to
be
addressed
to
achieve
the
desired
results.

The
most
important
issue
was
that
of
the
airtightness.
The
materials
used
for
the

chamber
were
proved
to
be
unsuitable
for
this
construction.
More
specifically,
the

plywood
base
was
a
poor
selection,
as
air
could
pass
through
the
pores
and
the

cracks
of
the
material.
To
add
to
that
in
an
effort
to
better
seal
the
joints
of
the
base,

silicone
caulk
was
used,
but
it
provided
minimum
protection.

Another
important

issue
that
could
be
redesigned
for
future
research
would
be
the
lid
of
the
chamber.

In
an
effort
to
make
the
lid
airtight,
rubber-‐foam
weather-‐seal
was
used.
This
was

not
enough
as
a
single
measure.
A
more
complex
way
for
ensuring
that
air
is
not

leaking
through
the
joints
of
the
top
part
of
the
chamber
is
necessary,
potentially
a

design
that
allows
the
lid
to
be
fastened
on
tightly
to
the
chamber.
Lastly,
the

107

construction
of
all
the
joints,
either
of
the
chamber
or
from
other
parts
attached
to

it,
should
be
reconsidered,
as
the
single
caulk
line
of
silicon
proved
to
not
be
enough.

For
results
to
be
considered
valid,
especially
in
a
lab
environment,
where
the

dilution
of
the
air
in
the
chamber
with
the
clean
lab
air
could
result
to
decrease

particle
mass
concentration,
it
was
suggested
that
the
reading
of
the
air
flow
meter

should
not
indicate
a
difference
more
than
30%,
from
the
inlet
to
the
outlet.

There
are
also
some
parameters
that
may
be
improved,
as
far
as
the
testing

procedure
is
concerned.
The
fact
that
the
airtightness
of
the
chambers
could
not
be

addressed
successfully
was
a
limitation
for
the
specific
study.
The
question
that

rises
is
whether
the
testing
results
would
be
even
more
encouraging,
if
ambient
air

was
not
infiltrating
the
interior
of
the
chamber,
at
the
final
setup
used.
Another

observation
is
that
with
a
more
airtight
chamber,
the
flow
rates
will
be
controlled

accurately.
Therefore
the
setup
will
be
able
to
include
the
airflow
rates
as
a

parameter,
which
appears
to
be
an
important
factor,
especially
when
expressed
as

an
air
exchange
rate.
Another
factor
that
could
be
important
may
be
the
ambient
air

concentration.
It
was
not
possible
to
test
different
ambient
air
mass
concentrations

and
determine
if
this
system
can
get
saturated
and
stop
working
effectively
after
an

ambient
particle
concentration
is
exceeded.
Lastly,
the
plant
foliage
geometry
might

also
be
a
factor
for
the
system
efficiency.
The
specific
plant
was
chosen
according
to

some
criteria
that
this
study
had
set.
However,
there
are
a
lot
more
plant
species

that
could
be
used
for
the
same
application
and
that
would
make
suitable
candidates

for
this
experiment.

108

6.2
IMPLEMENTATION

The
results
of
the
tests
are
promising
and
have
shown
an
average
reduction
of

number
concentration
of
particles
about
51.28%
for
the
maximum
surface
that
was

tested,
compared
to
the
ambient
air.
The
particles
filtered
are
mainly
secondary

particles,
which
are
the
more
toxic
for
humans,
as
they
are
still
chemically
active

and
easier
to
penetrate
the
respiratory
system
due
to
their
size.

As
discussed
above,
a
vegetated
façade
shows
potential
in
filtering
airborne

particles.
However,
it
cannot
completely
replace
the
mechanical
filtration
system

that
buildings
usually
use.
The
reason
is
that
the
vegetated
surface
appeared
to
be

successful
in
removing
particles
that
conventional
filters
may
not
be
able
to
address

particles
with
a
diameter
from
0.3μm
and
below.
The
efficiency
of
conventional

mechanical
filtration
systems
is
tested
for
particles
from
0.3μm
and
above.
Metrics

on
the
efficiency
of
those
systems
for
smaller
particles
do
not
exist.
Therefore,

phytofiltration
is
a
method
that
contributes
effectively
in
filtering
the
suspended

particles
with
a
small
diameter,
for
which
MERV
air-‐filters
efficacy
is
not
known,
but

for
bigger
particles
the
results
did
not
show
significant
reduction.
A
vegetated

facade
can
have
two
major
applications
that
could
benefit
indoor
air
quality:

− As
a
system
for
buildings
that
use
natural
ventilation
to
improve
IAQ
(Figure

6-‐2).
Mechanical
filtration
is
not
always
applied
to
buildings.
There
are
a
lot

of
buildings
that
up
to
this
day
use
natural
ventilation
and
they
do
not

109

include
a
filtration
system.
An
example
of
a
building
that
uses
natural

ventilation
for
some
of
its
spaces
is
the
San
Francisco
Federal
Building,
by

Thom
Mayne.

− Combined
with
another
filtration
system
(Figures
6-‐1,
6-‐3,
6-‐4),
that

addresses
particles
of
a
different
diameter
range.
This
system
could
either
be

mechanical,
a
high-‐MERV
filter,
or
another
material,
like
a
permeable
fabric.

In
this
case,
the
system
can
work
as
an
additional
measure
to
the
filtration

system
to
improve
IAQ.
This,
as
a
holistic
system
would
be
able
to
address

successfully
almost
the
entire
range
of
airborne
Particulate
Matter
that
could

be
introduced
in
the
interior
of
a
building.
Furthermore,
as
there
are

indications
that
this
system
can
address
an
amount
of
other
ranges
of

particles,
it
could
potentially
expand
the
lifecycle
of
the
filter
itself,
by

delaying
clogging
and
therefore
contribute
to
reducing
the
energy

consumption
that
is
a
result
of
improper
maintenance.

The
chart
below

illustrates
the
best
filtration
efficiency
measured,
in
addition
with
a
high

MERV
filter.

110

Figure
6-‐1:
Best
measured
efficiency
and
HighMERV
filter
combination

Figure
6-‐2:
Vegetated
surface
used
for
natural
ventilation.

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

10
100
1000
10000

Particle
Size
(nm)

Best
Measurement
and
High
MERV
hilter
combination
efhiciency

HighMERV
Vegetation

300

111

Figure
6-‐3:
Combination
of
vegetated
surface
and
HighMERV
filter
for
mechanical
ventilation.

Figure
6-‐4:
Combination
of
vegetated
surface
and
HighMERV
filter
for
natural
and
mechanical

ventilation.

Lastly,
it
was
noticed
that
even
in
the
base
case
testing,
when
the
chamber
was

empty,
there
was
some
particle
removal,
which
could
be
an
indication
that
even
just

a
double
skin
façade
might
be
able
to
provide
some
filtration
of
particles.

112

6.3
EXTRAPOLATION/
LARGE
SCALE
APPLICATION

The
extrapolation
of
the
system
is
based
on
estimations
of
the
data
that
have
been

acquired
during
the
experimental
process.
By
examining
the
trend-‐line
of
the
chart

illustrating
the
removal
efficiency
to
the
vegetated
surface
area,
a
prediction
can
be

made
about
the
maximum
removal
percentile
that
may
be
achieved.
The
chart

predicts
that
a
75%
removal
can
be
achieved
(Figure
6-‐5)
for
a
12ft
2

surface,
and

after
that
it
seemingly
decreases
again.
Understandably,
the
decrease
is
not
a

representative
prediction,
however
it
makes
sense
that
the
surface
will
have
an

upper
limit
of
removal
and
will
not
be
able
to
address
completely
the
entire
range
of

airborne
particles.

Figure
6-‐5:
Prediction
of
the
Maximum
Efficiency
of
the
surface.

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

0
2
4
6
8
10
12
14

Surface
Area
(ft
2
)

Removal
Percentile
to
Surface
Area

REDUCTION
REDUCTION
WET
LEAVES

REDUCTION
SIDES
VEGETATION

Reduction
Trend

113

An
estimation
of
the
percentile
of
particle
removal
ranging
from
0.01
μm
to
0.3
μm

was
attempted,
based
on
the
size
distribution
plot
measurement
for
the
biggest

surface
of
vegetation
tested
(Figure
5-‐4).
The
specific
range
was
isolated
for
three

reasons:

-‐ The
consistency
that
was
noticed
in
the
filtration
of
the
specific
sizes,

-‐ The
impact
that
the
specific
sizes
have
on
human
health,

-‐ There
are
no
data
on
how
well
conventional
MERV
filtration
systems
address

those
particles.

The
following
chart
shows
the
removal
measured
when
the
chamber
was
full,
the

estimated
removal
of
one
row
of
plants
and
the
maximum
efficiency
calculated

above
(Figure
6-‐6).

Figure
6-‐6:
Removal
Efficiency
Estimation
for
0.01μm
to
0.3μm

-‐5.00%

10.00%

25.00%

40.00%

55.00%

70.00%

85.00%

100.00%

10
60
110
160
210
260
310

Particle
Size
(nm)

Removal
Efhiciency
Estimation
for
Specihic
Particle
Sizes

maximum
measured
removal

maximum
estimated
removal
minimum
estimated
removal

114

Based
on
the
maximum
efficiency
estimations,
the
combination
of
the
vegetated

surface
with
the
HighMERV
filter
is
illustrated
at
the
following
figure
(Figure
6-‐7).

Figure
6-‐7:
Comparative
chart
of
the
predicted
and
best
measured
efficiency
of
vegetation
and

HighMERV
filter
combination

6.4
BENEFITS

There
are
certainly
many
benefits
in
the
large-‐scale
application
of
vegetated
facades

in
the
urban
built
environment.
These
can
be
performative
or
aesthetic.
As

mentioned
in
previous
chapters,
the
performance
of
such
systems
has
been
studied

for
many
different
parameters.
These
are:

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

10
100
1000
10000

Particle
Size
(nm)

Maximum
efhiciency
prediction
of
Vegetationn
and
HighMERV
hilter

combination

Best
Measurement
Prediction
Maximum

HighMERV
Vegetation

300

115

− Pollution
control.
This
was
the
scope
of
work
of
this
study.
It
was
observed

through
an
experimental
method
that
vegetated
surfaces
have
the
potential

of
removing
airborne
particles
of
a
specific
range.
The
removal
of
fine
dust

and
coarse
particulate
matter
by
the
plants
was
promising.
Towards
that

direction,
there
is
still
research
that
needs
to
be
done
to
determine
whether

plants
can
also
address
other
ranges
of
particles.
Furthermore,
from
previous

research
was
determined
that
specific
species
succeed
to
remediate
specific

chemical
pollutants.
However
PM2.5
has
the
biggest
impact
on
human
health.

By
using
plants
that
are
known
to
remediate
specific
pollutants
(NOx,
VOC’s

etc.),
in
environments
where
they
exceed
the
NAAQS,
this
problem
can
be

addressed
even
more
successfully.

− Shading.
Vegetated
facades
can
be
great
passive
shading
systems.
Depending

on
the
climate
and
the
orientation
of
the
façade
and
by
using
the
appropriate

species,
either
evergreen
or
deciduous,
the
passive
solar
gains
can
be

regulated
in
a
way
that
the
energy
performance
of
the
building
is
improved.

It
needs
to
be
added,
that
the
system
should
be
also
designed
in
a
way
that

does
not
obstruct
viewings
from
the
interior.

− Thermal
performance.
Apart
from
regulating
the
heat
gains
of
a
building
as
a

passive
shading
system,
a
vegetated
façade
can
also
work
as
a
thermal

insulation
system.
This
is
mostly
relevant
to
the
volume
of
the
vegetation
and

the
configuration,
however
studies
have
observed
decreased
surface

temperatures
when
they
were
covered
with
vegetation,
compared
to

surfaces
covered
by
traditional
building
materials
e.g.
brick,
glass.
It
must
be

116

noted
that
for
this
purpose
the
plant
species
selected
should
be
an
evergreen,

so
it
can
maintain
its
properties
consistently
throughout
the
year.

− Acoustics.
Vegetated
surfaces
have
been
greatly
used
to
reduce
noise

pollution
from
automotive
and
railway
routes.
Studies
conducted
have

shown
that,
for
living
wall
systems
the
sound
absorption
is
close
to
concrete,

but
this
is
also
more
relevant
to
the
material,
the
substrate
and
less
to
the

plant
species
used
70
.

− Aesthetics.
The
aesthetics
of
the
vegetated
surfaces
are
also
an
important

benefit
from
such
applications.
In
urban
built
environments
the
possibility
of

introducing
green
spaces,
like
urban
parks,
is
limited,
especially
in
dense

ones.
The
application
of
a
vegetated
façade
can
transform
the
building

envelope
into
a
visually
pleasing
surface.
Furthermore,
it
can
provide

aesthetic
variations
with
the
application
of
different
species,
with
different

volumes,
textures,
colors
and
growth
heights,
resulting
an
enhanced
optical

effect.

− Social.
Architecture
is
a
science
that
involves
social
implications.
Apart
from

the
aesthetic
and
performative
criteria
mentioned
above,
there
are
also

social
benefits
coming
from
the
application
of
such
systems
that
should
be

mentioned.
Vegetation
has
proved
to
have
an
impact
on
human
psychology.

There
have
been
various
studies
exploring
this
issue
that
have
shown
that

70

Wong,
Nyuk
Hien
et
al.
2010.
“Acoustics
evaluation
of
vertical
greenery
systems
for
building
walls”,
Building

and
Environment,
Volume
45,
Issue
2,
pp.
411-‐420.

117

vegetation
has
a
positive
effect
on
patient
recovery
and
on
stress
release.
71

To
add
to
that,
it
has
also
been
suggested
that
vegetation
can
improve

productivity
in
workplace
environments.
72

Lastly,
a
vegetated
surface
in
an

urban
built
environment
can
potentially
and
promote
sustainability
and
raise

awareness
of
the
inhabitants
to
claim
healthier
leaving
conditions
and

standards,
for
a
better
quality
of
life.

6.5
CONCERNS

Even
though
the
results
of
the
measurements
showed
some
significant
removal,

there
are
a
lot
of
arguments
that
can
be
made
and
should
be
further
investigated,

concerning
both
the
experimental
method,
as
well
as
the
application
of
the
system.

There
were
several
issues
that
occurred
during
the
testing
process
which
where

attempted
to
be
resolved,
some
in
a
more
successful
manner
than
others.
The
most

important
issue
was,
as
mentioned
several
times
before,
the
air-‐tightness
of
the

chambers,
a
problem
that
was
never
resolved
completely.
The
approach
that
was

followed
to
address
this
was
ultimately
the
best
possible,
but
it
was
also
an

approach
that
could
be
compromising
the
measurement
results,
as
ambient
air
was

infiltrating
the
chamber
and
possibly
increasing
the
final
particle
number

concentration.
It
was
a
solution
that
was
working
as
a
disadvantage
to
the
study
and

71

Ulrich
R.S
and
R.
Parsons,
1992.
“Influences
of
passive
experiences
with
plants
on
individual
well-‐being
and

health”,
The
Role
of
Horticulture
in
Human
Well-‐being
and
Social
Development,
Timber
Press,
Portland,
Oregon,
pp.

93-‐105,

72

Lohr,
Virginia
I.
et
al.
1996.
“Interior
Plants
May
Improve
Worker
Productivity
and
Reduce
Stress
in
a

Windowless
Environment”,
Journal
of
Environmental
Horticulture,
14(2
:),
pp.
97-‐100.

118

in
any
case
it
was
not
favoring
the
findings.
However,
it
was
assumed
to
be

reasonable
representation
of
the
real
world
problem.
The
question
that
still
remains

is
how
much
this
issue
actually
influenced
the
measurement
results
and
whether

those
results
would
be
improved
with
a
better-‐sealed
chamber.

There
are
also
several
considerations
that
occur
for
the
application
method.

− Effect
of
pollution
on
vegetation.
The
results
of
the
study
are
only
based
on

the
physical
properties
of
the
particles.
As
far
as
the
chemical
properties
of

these
particles
are
concerned
there
is
definitely
a
limitation
on
the
amount
of

pollutants
the
plants
can
uptake
and
break
down
through
their
metabolism

before
their
stomata
get
clogged
or
before
those
chemicals
have
an
impact
on

the
health
of
the
plants.
More
specifically,
nitrogen,
sulfur,
and
ozone,
which

are
common
gas
pollutants,
have
a
big
impact
on
plant
health.
That
should
be

one
of
the
main
concerns
of
the
designer,
as
the
visual
result
of
a
vegetated

façade
is
usually
the
main
reason
this
system
is
selected
to
be
applied
on
a

building.

− Species
selection.
This
leads
to
another
question
regarding
the
plant
species

selection.
The
plants
selected
for
the
purposes
of
this
study,
followed
specific

criteria
about
their
foliage
geometry,
their
endurance
in
specific
weather

conditions
and
their
growth
ability.
Apparently,
there
are
a
lot
more
plant

species
that
can
be
used
for
a
vegetated
façade.
However,
the
plant
species

selection
should
be
carefully
done
in
order
to
not
affect
the
indoor
air
quality.

The
plants
could
be
releasing
pollen
in
the
air
introduced
indoors,
causing

119

allergic
reactions,
or
even
worse,
other
toxic
substances
as
a
defense

mechanism
e.g.
Volatile
Organic
Compounds
are
emitted
from
some
plant

species
to
repel
insects

73
.
In
addition
to
that,
since
a
vegetated
surface
would

essentially
create
a
small
ecosystem
at
the
exterior
of
the
building,
it
is

possible
that
the
development
of
certain
microorganisms
and
insects,
which

get
transferred
in
the
interior
of
the
building,
could
also
have
an
impact
in

indoor
air
quality.

− Climate
conditions.
In
addition
to
the
above,
the
climate
conditions
should

also
be
carefully
examined
to
select
the
plant
species
and
under
the
concept

sustainability
native
species
should
be
preferred.
For
the
purposes
of
this

study,
the
plant
selected
was
a
native
plant
that
would
be
able
to
survive
the

weather
conditions
of
Los
Angeles.
It
is
very
likely
that
in
other
climate

zones,
the
specific
species
would
not
be
able
to
survive.

− Maintenance.
For
the
system
to
maintain
both
the
performative
as
well
as
the

decorative
function
appropriate
maintenance
is
necessary.
Again,
as
these

facades
are
essentially
living
organisms,
for
maintaining
their
health
and

avoiding
contamination
from
bacteria,
microorganisms
or
insects
the
use
of

herbicides
is
required.
The
use
of
these
substances
is
definitely
an
aspect
that

needs
careful
planning,
as
it
is
common
knowledge
that
those
contain

ingredients
harmful
to
humans,
and
their
penetration
into
indoor
spaces

should
be
certainly
avoided.
To
add
to
that,
maintenance
can
also
result
to

increased
generation
of
particles
that
can
be
introduced
indoors,
like
dust,

73

Freeman,
Brian
C.
and
Gwyn
A.
Beattie.
2008.
“An
Overview
of
Plant
Defenses
against
Pathogens
and

Herbivores”,
the
Plant
Heath
Instructor,
DOI:
10.1094/PHI-‐I-‐2008-‐0226-‐01.

120

soil
or
dead
cells
of
the
plants
when
being
trimmed.
Finally,
the
efficiency
of

the
system
in
the
case
that
the
plants
have
died
should
be
tested,
as
it
is
a

probable
scenario
when
the
system
is
applied.

− Irrigation
and
storm
water
management.
A
very
important
concern
is
the

irrigation
system
of
the
vegetated
façade.
Either
it
is
a
drip
system
or
a
spray

system;
it
is
only
up
to
a
certain
height
that
it
can
be
cost
effective.
The
cost

for
the
function
of
the
pump
providing
water
for
parts
of
the
vegetated

facades
that
exceed
this
height
increases
significantly.
There
are
solutions

that
could
be
further
studied,
like
a
greywater
irrigation
system
that
could

provide
immediately
water
for
these
heights,
or
collecting
rainwater
on
the

roof,
to
later
use
it
for
irrigation.
Another
concern
is
that,
the
surplus
of

water,
either
coming
from
the
irrigation
system,
either
from
weather

conditions
should
be
carefully
handled.
The
façade
should
be
designed
in

such
way
that
it
will
not
allow
water
penetrating
its
components,
or
even

worse,
the
curtain
wall
components
of
the
building.
Moreover,
it
should
not

allow
water
to
be
retained
in
various
parts,
because
the
moisture
created

could
potentially
damage
parts
of
the
façade,
or
the
curtain
wall.

− Overall
living
conditions
of
plants.
Depending
on
the
species
selection,
the

living
conditions
of
the
plants
should
be
examined
and
design
the
system
in

accordance.
These
conditions
include
sunlight
exposure,
growing
substrate

type;
irrigation
needs,
life
span,
durability
etc.

− Cost.
Vegetated
facades
have
high
installation
costs
and
specific
maintenance

needs
that
need
to
be
addressed.
They
are
systems
that
have
recently
started

121

to
be
broadly
applied
on
buildings,
therefore,
the
payback
period
is
not
yet

known.
To
add
to
that,
the
installation
cost,
compared
to
the
savings
from
the

reduction
of
the
energy
consumption,
is
still
under
study.

− Humidity
and
moisture
control.
Through
the
natural
process
of

evapotranspiration
water
vapor
is
released
from
plants
and
the
soil.
A
very

important
parameter
of
indoor
air
quality
is
humidity.

To
ensure
the
user

comfort
of
indoor
spaces,
a
regulating
system
to
control
the
amount
of
water

vapor
that
is
introduced
in
the
interior
of
the
building,
along
with
the
clean

air
should
also
be
considered.

− Wind
velocity
on
the
vegetated
surface.
The
air
was
pulled
through
the

chamber
with
a
pump.
The
flow
rate
was
measured
at
the
outlet
of
the

chamber
and
it
was
50lt/m.
The
maximum
possible
wind
velocity
at
the

vegetated
surface
would
be
0.012m/s.

However,
since
it
was
realized
that

the
flow
rates
was
not
consistent,
this
is
only
an
assumption.
To
add
to
that,

when
the
system
is
used
to
improve
air
quality
of
a
natural
ventilated

building
there
will
be
different
wind
velocities
for
different
months
and

seasons
and
sometimes
even
still
air
days.
This
is
a
fragment
of
the
study
that

was
intended
to
be
studied,
the
way
different
flow
rates
may
affect
the

filtration
properties
of
the
vegetation,
but
due
to
lack
of
airtightness
of
the

chambers,
it
was
not
accomplished.

122

Chapter
Seven:
Future
Work

The
study
focused
on
determining
whether
a
vegetated
façade
can
work
as
a
filter
to

reduce
airborne
fine
particulate
matter
infiltrating
interior
spaces
and
therefore

improve
indoor
air
quality
for
the
users
of
the
building.
That
required
the

construction
of
a
physical
test-‐cell
that
would
allow
performing
measurements
to

determine
that.
Throughout
the
study
many
problems
occurred,
some
of
them
were

successfully
addressed,
others
were
documented
and
not
completely
resolved.
The

results
of
the
measurements
taken
were
encouraging
and
show
potential
that
a

vegetated
surface
can
indeed
remove
particles
of
a
specific
size.
However,
due
to
the

limitations
presented,
it
is
still
too
soon
to
make
a
general
statement
that
all

vegetated
facades
can
successfully
address
fine
particulate
matter.
Overall,
the
study

has
set
a
base
for
the
further
exploration
and
improvement
of
the
experimental

method
as
well
as
the
possibility
and
feasibility
of
the
architectural
application.

7.1
IMPROVEMENT
OF
THE
EXPERIMENTAL
METHOD

The
limitations
of
the
study
encountered
through
the
experimental
method
can
be

improved
to
repeat
the
measurements
and
validate
the
results.
The
most
important

parameters
would
be:

-‐ Infiltration.
Improving
the
design
of
the
chambers
could
lead
to
different

results
demonstrating
less
or
more
filtration
efficiency.

123

-‐ Volumetric
flow
rate.
As
a
continuation
of
the
above,
when
the
infiltration
is

not
a
limitation,
different
flow
rates
can
be
examined
to
determine
the

impact
of
wind
velocity
to
filtration
efficiency.

-‐ The
chamber
dimensions.
The
chambers
constructed
had
given
dimensions.

A
bigger
chamber
allowing
a
larger
surface
area
to
be
tested
will
give
a
better

understanding
of
the
total
amount
filtration
that
can
be
achieved
and
if
that

could
reach
100%
for
a
specific
area.

-‐ Plants.
The
study
only
tested
a
specific
plant
species
with
specific
foliage

geometry.
Different
leaf
geometries
could
result
different
filtration
efficiency.

-‐ Weather
conditions.
The
weather
conditions
can
have
an
impact
on
the

filtration
efficiency.
Humidity
and
sunlight
are
two
factors
that
affect
the

levels
of
particulate
matter
in
the
ambient
air
and
could
affect
the

measurement
results.

-‐

7.2
ARCHITECTURAL
APPLICATION

The
architectural
application
was
briefly
examined
in
this
study.
Further

exploration
of
the
vegetated
façade
as
an
architectural
solution
may
also
be
useful
in

determining
if
a
vegetated
façade
could
be
feasible
as
an
air-‐filtration
medium:

-‐ Computational
Fluid
Dynamic
Analysis.
The
air
movement
on
the
vegetated

surface
can
be
studied
to
determine
what
amount
of
air
that
is
filtered
by
the

plants
can
reach
indoors
for
naturally
ventilated
building.
Different
wind

velocities
may
be
examined
for
different
scenarios
and
climates.
This
can
also

humidity
and
air
temperature.

124

-‐ Irrigation
system.
The
efficacy
and
cost
effectiveness
of
the
irrigation
system

can
also
be
examined.
The
cost
and
the
energy
consumption
of
a
system
like

that
can
dramatically
increase
as
the
building
height
increases.
The
point
at

which
the
cost
of
this
system
is
getting
larger
than
the
benefits
remains
a

question.
Another
direction
in
this
area
that
can
be
further
explored
is
the

potential
use
of
a
greywater
system,
or
a
rainwater
harvesting
system
for

irrigation.

-‐ Daylight
Analysis.
One
of
the
applications
suggested
in
this
study
is
a

horizontal
shelf
configuration.
The
optimization
of
the
shelf
depth
for
the

plants
to
get
adequate
light
for
their
survival
and
at
the
same
time
the
indoor

conditions
is
an
area
leaves
a
lot
of
room
for
further
research.

-‐ Smart
components.
The
addition
of
smart
components
can
also
be
a
useful

for
the
architectural
application.
The
façade
could
be
able
to
sense
the
indoor

air
quality
and
the
ambient
air
quality
and
make
a
decision
on
whether
the

interior
needs
to
be
ventilated
and
if
the
filtered
air
quality
will
improve
the

occupants
comfort
levels.
This
could
also
include
the
air
temperature
and

humidity
to
achieve
even
higher
levels
of
user
comfort.

125

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127

ONLINE
RESOURCES:

1. Wikipedia:
http://www.wikipedia.com/

2. ASHRAE:
http://www.ashrae.org/

3. National
Air
Filtration
Association:
http://www.nafahq.org/

4. Environmental
Protection
Agency:
http://www.epa.gov

5.
Air
Quality
Management
District:
http://www.aqmd.gov

6. British
Columbia
Air
Quality
Site:
http://www.bcairquality.ca/

7. Clean
Air
World
Site:
http://www.cleanairworld.org/

8. Engineering
Toolbox
Site:
http://www.engineeringtoolbox.com/

128

APPENDIX
A:
Description
of
the
Setups
Used
and
Results

A.1
INITIAL
SETUP
OF
THE
ENVIRONMENTAL
CHAMBER

The
initial
set
up
of
the
chamber
was
that
of
a
single
chamber
using
Sharp

GP2Y1010AU0F
Optical
Dust
Sensors
to
measure
the
particle
mass
concentration
at

the
inlet
and
the
outlet.
The
fan
used
to
push
particles
inside
the
chamber
was
an

Altwood
Turbo
4000
fan.
The
fans
speed
was
not
adjustable
so
it
was
connected
to

an
electronic
step-‐less
speed
control
in
order
to
change
the
air
velocity
in
the

chamber.
The
original
setup
is
illustrated
at
diagram
bellow
(figure
A-‐1).

Figure
A-‐1:
Initial
setup
of
the
environmantal
chamber

129

A.1.1
Images
and
details
of
the
initial
setup

Images
and
details
of
the
finished
environmental
chamber:

Figure
A-‐2:
Finished
Chamber

Figure
A-‐3:
Environmental
Chamber
Full
Set-‐Up

130

Figure
A-‐4:
The
Arduino
Boards
Connected
to
the
LED
displays

Figure
A-‐5:
The
Sensors
mounted
in
the
PVC
pipes

131

Figure
A-‐6:
The
Electronic
Step-‐Less
Speed
Control

A.1.2
Sensors

The
sensors
selected
to
measure
the
amount
of
particulate
matter
were
two
Sharp

GP2Y1010AU0F
Optical
Dust
Sensors,
connected
to
Arduino
boards.
The
operation

of
the
sensors
is
the
following.

The Sharp Optical Dust Sensors, according to the specification sheet, have
an
infrared

emitting
diode
(IRED)
and
a
phototransistor
that
are
diagonally
arranged
into
the

device.
It
detects
the
reflected
light
of
dust
in
air.

Especially,
it
is
effective
to
detect

very
fine
particle
like
the
cigarette
smoke.

In
addition,
the
sensitivity
can
be

adjusted
so
it
can
distinguish
smoke
from
house
dust
by
pulse
pattern
of
output

voltage.
The
sensors
output
is
an
analog
voltage
proportional
to
the
measured
dust

132

density,
with
sensitivity
of
0.5V
/
0.1
mg/m
3
.

74

Therefore
the
sensors
are
sensitive

enough
to
detect
particles
belonging
in
the
E1
group,
according
to
ASHRAE
52.2-‐
2007
standards.

The
Sensors
were
then
connected
to
Arduino
boards
to
translate
and
record
the

measurements.
The
results
were
reported
in
Volt
and
based
on
the
specifications
of

the
sensors
the
following
equation
was
applied
to
convert
the
results:

-‐ From
Volts
to
mg/m
3
:

(V
–
0.9)/K,
where:

V:
Voltage
output

K:
Sensitivity
of
sensor
(since
a
change
in
the
voltage
output
of
0.5
means
a

0.1
change
in
the
dust
concentration
in
the
typical
mode,
the
sensitivity
is

0.5/0.1)

0.9:
the
sensor
output
when
no
dust
is
present
is
typically
0.9
Volts,
which

should
be
deducted
from
the
total
output.

The
Arduino
boards
were
connected
to
LED
displays,
showing
the
particle

concentrations
so
any
change
from
the
intake
to
the
outtake
would
be
immediately

noticed
and
recorded.

74

Source:
http://www.sparkfun.com/datasheets/Sensors/gp2y1010au_e.pdf

133

A.1.3
Testing
Procedure
and
Results

Some
initial
tests
were
conducted
in
order
to
determine
whether
the
environmental

chamber
was
working
as
expected.
For
those
tests
the
results
were
not
recorder.

The
efficiency
of
the
chamber
was
based
on
the
variation
of
the
LED
displays
output

for
the
intake
and
outtake.

In
order
to
simulate
the
particle
size
of
combustion
products
that
their
range
is
up

to
2.5μm
the
particle
size
of
some
commonly
available
products
was
examined
in

order
to
determine
what
could
substitute
these
pollutants.
The
following
table

(table
a-‐1)
shows
the
particles
chosen
compared
to
the
size
of
atmospheric
dust.

Table
A-‐1:
Particle
Sizes
75

Particles

Size
in
microns
(μm)

Atmospheric
Dust
0.001
–
40

Cornstarch
0.1
–
0.8

Tobacco
Smoke
0.01
-‐
4

After
it
was
confirmed
that
the
sensors
and
the
chamber
were
working

appropriately
the
recorded
preliminary
tests
begun.
For
a
particle
sources
match

smoke
and
cornstarch
was
used.
For
each
particle
type
more
than
one
tests
were

performed
at
different
fan
speeds.
In
total
12
preliminary
tests
were
conducted
in
a

25
minute
period.
The
preliminary
results
are
presented
in
the
following
charts.

75

Source:
http://www.engineeringtoolbox.com/particle-‐sizes-‐d_934.html

134

Figure
A-‐7:
Averaged
Control
Measurement
#2,
Particle
Source:
Cornstarch,
Fan
Speed:
High

Figure
A-‐8:
Averaged
Control
Measurement
#6,
Particle
Source:
Cornstarch,
Fan
Speed:
Low

-‐0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0:00
0:10

Paerticle
Concentration
(μg/m^3)

Time
(minutes)

Averaged
Control
Measurements
#2

Average
Inlet
Concentration
Average
Outlet
Concentration

0

0.1

0.2

0.3

0.4

0.5

0.6

0:00
0:10
0:20
0:30
0:40
0:50

Particle
Concentration
(μg/m^3)

time
(minutes)

Averaged
Control
Measurements
#6

Average
Inlet
Concentration
Average
Outlet
Concentration

135

Figure
A-‐9:
Test#1
Particle
Source:
Match
Smoke,
Fan
Speed:
Low

Figure
A-‐10:
Test#3,
Particle
Source:
Match
Smoke,
Fan
Speed:
High

-‐0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0:00
0:10
0:20
0:30
0:40
0:50
1:00
1:10
1:20
1:30

Particles
Concentration
(μg/m^3)

Time
(minutes)

Test
#1

intake
Cncentration
outtake
Cncentration

-‐0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0:00
0:10
0:20
0:30
0:40
0:50

Particle
Concentration
(μg/m^3)

Time
(minutes)

Test
#3

intake
Concentration
outtake
Concentration

136

Figure
A-‐11:
Test#5,
Particle
Source:
Cornstarch,
Fan
Speed:
High

Figure
A-‐12:
Test#11,
Particle
Source:
Cornstarch,
Fan
Speed:
Low

-‐0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0:00
0:10
0:20

Particle
Concentration
(μg/m^3)

Time
(minutes)

Test
#5

intake
Concentration
outtake
Concentration

-‐0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0:00
0:10
0:20
0:30

Particle
Concentration
(μg/m^3)

Time
(minutes)

Test
#11

intake
Concentration
outtake
Concentration

137

The
time
period
for
each
test
was
from
1:30
minutes
to
0:20
minutes.
The

environmental
chamber
was
designed
to
measure
the
particle
concentration
in
the

intake
and
the
outtake.
Similarly
to
a
conventional
MERV
filter,
what
is
measured
is

the
amount
of
particles
deposited
directly
on
the
filter,
which
in
this
case
is
the

foliage,
and
withheld
on
it.
This
amount
of
particles
can
be
assumed
that
will
be

gradually
absorbed
and
broken
down
by
the
plant.
The
time
period
for
each
test
was

determined
to
be
from
the
time
that
the
particles
were
inserted
in
the
duct
leading

to
the
filter,
to
the
time
the
outtake
sensor
indication
on
the
LED
display
returned
to

the
minimum
amount
of
concentration,
indicating
that
all
of
the
particles
were

either
deposited
on
the
leaves,
or
passed
through
to
the
outtake.

The
results
of
the
measurements
showed
some
filtration
potential
when
the

chamber
was
full
of
plants
compared
to
the
control
measurements
with
the
same

fan
speed
and
an
empty
chamber.
These
preliminary
conclusions
indicated
that

filtration
was
relative
to
the
particle
size
and
the
air
velocity
inside
the
chamber.

However
there
are
some
components
that
need
to
be
further
examined
in
order
to

be
able
to
state
that.
These
parameters
are
described
bellow.

A.1.4
What
went
wrong

Some
of
the
parameters
that
may
be
affecting
the
results
of
the
preliminary
tests

needed
to
be
taken
into
consideration
to
determine
their
impact
on
the
testing

results.
These
parameters
were
the
following.

138

The
air
velocity
in
the
environmental
chamber
was
an
important
parameter
that

through
the
first
measurements
affected
the
results.
With
the
fan
speed
set
at
higher

settings
for
both
the
particle
sources,
there
was
not
a
difference,
for
the
intake
and

the
outtake.
However
for
the
lower
settings,
there
was
noticed
some
filtration,

depending
on
the
particles
used
for
the
testing.
Furthermore,
the
fan
speed
was

controlled
by
an
electronic
step-‐less
speed
control,
which
made
it
impossible
to

duplicate
the
same
fan
speed
for
more
multiple
tests.

This
issue
could
be
easily

addressed
through
an
air-‐velocity
meter,
either
handheld
or
other.

Another
important
parameter
was
the
particle
source
itself.
For
the
preliminary

tests,
the
amount
of
particles
introduced
in
the
chamber
was
not
accurately

controlled,
which
means
that
for
the
same
particle
source,
the
concentration
of

particles
at
the
intake
could
be
different.
It
is
possible
that
this
by
itself
might
affect

the
results,
as
for
a
bigger
amount
of
particles;
the
amount
deposited
on
the
foliage

of
the
plants
might
be
too
small
to
be
detected.

The
sensors
themselves
could
also
be
a
parameter
that
might
create
an
issue
into

not
getting
accurate
enough
results.
The
sensors
selected
have
a
threshold
of

measuring
concentration
of
particles.
Specifically,
the
sensor
has
a
maximum
output

of
about
3.5V,
which
is
equivalent,
based
on
the
translating
equation
used,
to
0.6

mg/m
3
.
Changes
beyond
that
threshold
might
not
be
detectable.
Furthermore,
the

sensors
might
not
be
sensitive
enough
to
detect
slight
changes
in
the
concentration

at
the
intake
and
the
outtake.
This
problem
could
be
addressed
either
by
adjusting

139

the
equation
that
translates
the
output
voltage
of
these
sensors,
or
by
using

different,
more
sensitive
ones.
The
equation
used
to
translate
the
results
was
(V
–

0.9)/K,
based
on
the
specification
sheet
of
the
sensors.
However,
for
the
specific

application
an
Internet
tutorial
suggested
that
the
concentration
should
be

translated
by
this
equation
C
=
0.172
*
V
-‐
0.0999
76
.
As
a
change
of
one
Volt
in
the

output,
is
translated
to
a
204.6
step
by
the
Arduino
board,
an
equation
that
will
be

able
to
translate
smaller
decimal
changes
into
concentration
might
be
able
to

provide
more
accurate
readings
for
changes
smaller
than
one
decimal
as
an
output.

A.2
SECOND
SETUP

After
consulting
with
the
Aerosol
lab
of
the
USC
School
of
Civil
and
Environmental

Engineering
the
initial
setup
of
the
chambers
was
revised
to
better
represent
the

conditions
of
the
problem
trying
to
be
simulated
(Figure
A-‐13).

Figure
A-‐13:
Second
setup
of
the
environmental
chamber

The
first
improvement
was
that
another
chamber
was
required
to
be
built
to

represent
the
indoor
space
while
the
original
chamber
would
represent
the

conditions
of
the
ambient
air.
The
size
of
the
opening
of
the
second
chamber,

76

“Air
Quality
Monitoring”
site.
http://www.howmuchsnow.com/arduino/airquality/

140

allowing
the
ambient
air
to
enter
the
indoor
space,
was
based
on
the
Title
24

standard
for
natural
ventilation:

“The sum of the areas of the openings must total at least 5 percent of the floor area of
each space that is naturally ventilated.”
77

The
position
of
the
pump
that
would
move
the
particles
inside
the
configuration

was
placed
at
the
outlet.
This
was
done
because
pulling
the
particles
would
simulate

better
the
effect
of
an
opening
that
is
used
for
ventilation
and
the
penetration
of

ambient
air
to
an
indoors
space.

A.2.1
Images
of
the
second
setup

Images
and
details
of
the
second
setup

Figure
A-‐14:
The
chambers
second
setup
at
the
Aerosol
Lab

77

“Title
24
ventilation
requirements
for
non-‐residential
occupied
spaces”

141

Figure
A-‐15:
Inlet,
the
connection
to
the
aerosol
generator
and
the
DustTrak
Aerosol
Monitor
measuring

mass
concentration

Figure
A-‐16:
Outlet,
connection
to
the
pump
and
the
Aerosol
DustTrak
Monitor
measuring
mass

concentration

142

Figure
A-‐17:
Connection
of
the
two
chambers

Figure
A-‐18:
The
aerosol
generator

143

Figure
A-‐19:
Measurement
with
the
chamber
full
of
plants

Figure
4ration
test
with
water
penetrating
the
chamber
from
the
plywood
bottom

A.2.2
Sensors
and
testing
Procedure

The
new
setup
was
transferred
at
the
Aerosol
Lab,
where
the
appropriate

equipment
was
provided
to
make
more
accurate
measurements.
The
sensors
used

for
this
setup
were
the
DustTrak
Aerosol
monitors,
described
in
chapter
3.
An

144

aerosol
generator
was
connected
to
the
inlet
of
the
chamber
representing
the

outdoors
space.
An
Ammonium
Sulfate
aerosol
was
used,
which
is
better
for

modeling
secondary
outdoor
particles.
A
pump
was
connected
at
the
outlet
of
the

chamber
representing
the
indoor
space.
The
pump
was
set
to
pull
air
at
a
steady

flow
rate
of
60lt/m.
In
order
for
the
test
to
be
more
realistic,
the
air
exchange
rate

should
be
about
1
change
per
hour,
but
since
scaling
down
the
space
of
the
indoor

space
for
the
purpose
of
modeling,
it
was
acceptable
that
the
air
exchange
rate

would
increase.

The
testing
procedure
was
simple.
The
aerosol
generator
would
produce
particles

continuously
and
therefore,
the
output
of
the
aerosol
monitor
connected
to
the
inlet

would
remain
the
same
throughout
the
measurements
with
slight
deviations.
The

second
aerosol
monitor
would
display
the
concentration
of
particles
at
the
outlet.

For
each
configuration
of
plants,
as
soon
as
the
reading
would
stabilize
without
any

serious
deviations
(more
than
0.1mg/m
3
)
it
was
considered
that
this
would

represent
the
concentration
of
particles
in
the
chamber
representing
the
indoors

space.
The
initial
concentration
of
the
aerosol
was
set
at
20.5
mg/m
3
.

The
configurations
of
the
plants
inside
the
chamber
were
the
same
as
the
ones
used

for
the
final
setup.
The
results
for
all
of
those
measurements
showed
absolutely
no

difference
when
the
chamber
was
empty
to
when
the
chamber
was
full
of
plants.

The
initial
particle
concentration
was
about
20.5
mg/m
3

with
slight
deviations
and

the
reading
of
the
aerosol
monitor
connected
to
the
outlet
would
consistently

145

stabilize
at
about
6mg/m
3
.
Although
this
could
be
an
encouraging
result
when
the

chamber
was
full
of
plants,
it
was
not
justifiable
when
performing
the
control

measurement
with
the
empty
box.

A.2.3
What
went
wrong

By
examining
the
results
of
the
second
setup,
the
first
reason
that
would
rationalize

those
values
would
be
to
determine
if
there
was
a
leak.
The
leak
test
showed
that

both
of
the
chambers
were
not
properly
sealed.
A
flow
meter
was
connected
to
the

outlet,
where
the
pump
was
pulling
air.
The
indication
was
60lt/m.
The
flow
meter

was
then
connected
to
the
inlet
and
the
airflow
at
that
side
was
less
than
10lt/m.

For
figuring
out
where
the
leaks
were,
the
inlet
was
sealed
and
the
pump
was
left
to

draw
air
from
the
chambers.
Water
was
then
sprayed
around
the
edges
and
the

joints
to
see
whether
specific
joints
were
leaking.
Unfortunately,
the
environmental

chamber
with
the
plywood
base
was
a
big
issue,
as
air
was
infiltrating
through
the

cracks
and
pores
of
the
base
(figure
A-‐20).
The
water
was
instantly
pulled
up
by
the

difference
of
air
pressure
inside
and
outside
of
the
chamber.
Again,
the
same

procedure
was
performed
with
the
smaller
chamber,
but
it
was
not
possible
to

overcome
the
leaking
problems.

The
results
of
the
measurements
could
than
be
explained.
The
chambers
were

leaking
so
much
that
the
air
from
the
chambers
was
leaking
out,
and
clean
air
from

the
lab
was
infiltrating.
The
air
in
the
chamber
was
diluted
so
much
that
it
would

always
end
up
having
the
same
particle
concentration
for
all
the
measurements.

146

Through
this
process
the
parameters
that
were
noted
as
problematic
at
the
initial

setup
could
be
controlled.
Those
were
the
amount
and
consistency
of
the
particle

sample
introduced
inside
the
chamber,
a
better
control
of
the
airflow
rate
inside
the

chambers
and
accurate
equipment
for
documentation.
However
a
new
problem
was

discovered,
that
of
the
airtightness
of
the
chambers
used.
In
order
to
get
more

accurate
results,
the
chambers
need
to
be
sealed
so
the
air
inside
them
will
not
get

mixed
up
and
diluted
with
air
that
it’s
particle
concentration
cannot
be
controlled.

147

APPENDIX
B:
Calculations
for
the
Architectural
Application

Based
on
the
results
of
the
physical
experiments,
some
calculations
were
attempted

to
make
a
rough
estimation
on
the
amount
of
the
vegetated
surface
needed
to
cover

the
ventilation
needs
of
a
typical
office
space.
These
calculations
were
made,
by

making
assumptions
on
the
efficiency
of
the
system
as
the
vegetated
area
increases

and
the
time
needed
for
a
specific
air
volume
to
be
cleaned.

Given
data:

1. The
total
volume
of
the
chamber
is
18”x18”x36”=
11,664
in
3

=

6.75
ft
3
.

The
total
height
of
the
chamber
is
18”,

The
adjustable
platform
height
is
7”
from
the
bottom,

The
height
of
the
pots
is
5”,

The
height
of
the
foliage
is
6”.

The
volume
of
air
that
can
be
assumed
that
was
cleaned
was
the
air
from
the

top
of
the
pots
of
the
plants
to
the
lid
of
the
chamber
(figure
b-‐1).

Figure
B-‐1:
Volume
of
air
used
for
the
calculations.

2. A
typical
office
space
has
14’x10’x12’
dimensions,
where
9’
is
the
net
height

of
the
office.

148

The
total
volume
of
this
space
is
9’x10’x12’=1,080
ft
3
.

Assume
that
the
vegetated
surface
is
placed
on
the
largest
side,
12’

Figure
B-‐2:
Dimensions
of
a
typical
office
space.

3. According
to
the
engineering
toolbox
site
the
typical
exchange
rate
for
a

private
office
per
hour
is
4.

That
means
the
total
volume
of
air
is
renewed
every
15
minutes.

4. The
time
needed
to
clean
the
specific
volume
of
air
of
the
chamber
was
about

5
minutes.

This
is
concluded
by
the
time
the
particle
counter
reading
took
to
stabilize.

(When
the
particle
counter
reached
a
range
that
indicated
that
there
would

be
no
further
increase
or
reduction.)

• By
calculating
the
volume
of
air
moving
through
the
foliage
of
the
plants.

The
height
of
the
volume
calculated
will
be
6”

The
volume
of
the
air
the
chamber
cleans
is:

6”x18”x36”=
3,888
in
3

=
2.25
ft
3

The
chamber
needs
5
minutes
to
clean
a
volume
of
2.
25
ft
3

At
15
minutes
time
the
chamber
cleans
2.25x3
=
6.75
ft
3
.

149

To
clean
1,080
ft
3

of
air
volume
in
15
minutes
the
chambers
needed
are:

1,080/6.75=
160.

If
the
vegetated
surface
is
placed
by
its
smallest
dimension
(1.5’),

on
one
row
on
the
façade
8
chambers
can
be
placed.

160/8=
20
rows

The
total
amount
of
vegetated
surface
needed
will
be

(18”x36”)x8x20=103,680in
2

or
720ft
2
.

The
height
of
the
façade
is
9
feet.

That
means
that
the
rows
will
be
placed
with
about
5.4”
spacing.

For
the
total
height
of
the
floor
14
feet
total
height

0.7
feet
spacing,
8.4”

Figure
B-‐3:
Horizontal
Shelves,
36"
Depth,
20
rows.

• By
increasing
the
shelves
depth
and
assuming
that
the
time
taken
to
clean

the
air
volume
still
remains
5
minutes,
which
would
correspond
to
increasing

the
flow
rate
during
the
physical
testing:

• If
the
depth
of
the
shelf
is
48”
Than
the
total
surface
area
of
one
shelf
will
be:

18”x48”=864
in
2

or
6ft
2
.

According
to
the
trend-‐line
of
figure
6-‐3
this
also
increases
the
efficiency
at

60%

If
720ft
2

of
total
vegetated
surface
are
required,
and
the
area
of
one
shelf
is

6ft
2
,
than
720/6=
120
shelves.
One
row
will
have
8
shelves,
so
120/8=
15

Total
will
be
15
rows,
at
0.93
feet
or
11.16”
equal
spacing.

150

Figure
B-‐4:
Horizontal
Shelves,
48"
Depth,
15
rows
equally
spaced.

Or,
for
allowing
viewing
outdoors

Figure
B-‐5:
Horizontal
Shelves,
48"
Depth,
15
rows.

• If
the
depth
of
the
shelf
is
54”
Than
the
total
surface
area
of
one
shelf
will
be:

18”x54”=972
in
2

or
6.75ft
2
.

According
to
the
trend-‐line
of
figure
6-‐3
this
also
increases
the
efficiency
at

about
63%

If
720ft
2

of
total
vegetated
surface
are
required,
and
the
area
of
one
shelf
is

6.75ft
2
,
than
720/6=
107
shelves.
One
row
will
have
8
shelves,
so
107/8=
13

Total
will
be
13
rows,
at
1.07
feet
or
12.8”
equal
spacing.

151

Figure
B-‐6:
Horizontal
Shelves,
54”
Depth,
13
rows
equally
spaced.

Or,
for
allowing
viewing
outdoors

Figure
B-‐7:
Horizontal
Shelves,
54"
Depth,
13
rows.

• If
the
depth
of
the
shelf
is
60”
Than
the
total
surface
area
of
one
shelf
will
be:

18”x60”=1,080
in
2

or
7.5ft
2
.

According
to
the
trend-‐line
of
figure
6-‐3
this
also
increases
the
efficiency
at

about
67%

If
720ft
2

of
total
vegetated
surface
are
required,
and
the
area
of
one
shelf
is

7.5ft
2
,
than
720/7.5=
96
shelves.
One
row
will
have
8
shelves,
so
107/8=
12

152

Total
will
be
12
rows,
at
1.17
feet
or
14”equal
spacing.

Figure
B-‐8:
Horizontal
Shelves,
60”
Depth,
12
rows
equally
spaced.

Or,
for
allowing
viewing
outdoors,

Figure
B-‐9:
Horizontal
Shelves,
60"
Depth,
12
rows.

• If
the
depth
of
the
shelf
is
72”
Than
the
total
surface
area
of
one
shelf
will
be:

18”x60”=1,296
in
2

or
9ft
2
.

According
to
the
trend-‐line
of
figure
6-‐3
this
also
increases
the
efficiency
at

about
70%

153

If
720ft
2

of
total
vegetated
surface
are
required,
and
the
area
of
one
shelf
is

9ft
2
,
than
720/9=
80
shelves.
One
row
will
have
8
shelves,
so
80/8=
10

Total
will
be
10
rows,
at
1.4
feet
or
16.8”
equal
spacing.

Figure
B-‐10:
Horizontal
Shelves,
72"
Depth,
10
rows
equally
spaced.

Or,
for
allowing
viewing
outdoors

Figure
B-‐11:
Horizontal
Shelves,
72"
Depth,
10
rows.

VERTICAL
SQUARE
PANEL

154

• If
I
have
18”x18”
vertical
square
panels:

The
total
area
of
one
panel
will
be:

18”x18”=324
in
2

or
2.25
ft
2

If
it
takes
5
minutes
for
the
air
to
be
cleaned
by
a
4.5
ft
2

surface
area

For
2.25
ft
2

it
will
need
about
2.5
minutes.

The
volume
cleaned
in
15
minutes
will
be
2.25x6=13.5ft
3

To
clean
1,080
ft
3

of
air
volume
in
15
minutes
the
panels
needed
are:

1,080/13.5=
80.

That
is
a
total
surface
area
of
80x2.25=180ft
2

The
total
available
surface
is
14x12=
168
ft
2

This
means
76
square
panels,
which
is
an
acceptable
result
if
the
entire

vertical
surface
is
covered
by
panels.

Figure
B-‐12:
Vertical
Panels.

Opening
Size:

If
the
boxes
are
160
and
each
box
has
a
12.56in
2

opening

Total
opening
is
2009in
2

which
is
13.95ft
2

As
title
24
indicates
5%
of
floor
area
should
be
the
opening

155

Total
floor
area
of
the
office
is
120ft
2
.

The
minimum
total
area
of
openings
indicated
by
Title24
for
natural

ventilation,
is
5%,
which
is
6ft
2
.

The
calculations
above
where
done
with
specific
assumptions
concerning
the
time

needed
for
the
air
volume
to
be
cleaned
and
the
efficiency
of
the
system.
The
vertical

system
appears
to
be
more
suitable
for
applying
it
on
a
façade,
based
on
these

calculations.

156

APPENDIX
C:
Preliminary
CFD
and
Daylight
Studies

Within
the
context
of
the
architectural
application,
two
preliminary
studies
were

also
performed
to
examine
if
the
vegetated
façade,
as
the
system
that
the
thesis

proposed,
would
be
a
possible
and
efficient
application.
These
studies
could
be

subject
to
further
analysis
and
not
in
the
scope
of
work
of
this
thesis.
However,
they

constituted
a
useful
exercise
to
examine
the
feasibility
of
the
system
as
a
complete

architectural
application.
Three
different
configurations
were
chosen,
based
on
the

calculations
made
that
offered
the
best
potential
as
a
façade
system.
The
sections
of

the
three
systems
tested
are
presented
below
(Figures
C-‐1,
C-‐2,
C-‐3).

Figure
C-‐1:
Horizontal
Shelves,
Depth
72",
section

157

Figure
C-‐2:
Horizontal
Shelves
equally
spaced,
72"
Depth,
section

Figure
C-‐3:
Vertical
Panels
18"x18",
section

C.1
AIR-‐FLOW
STUDY

A
preliminary
air-‐flow
study
was
performed,
as
wind
movement
and
wind
velocity

through
the
foliage
of
the
vegetated
surfaces
would
indicate
whether
the
application

would
be
successful
or
not.
The
speed
of
the
air
should
increase
as
it
passed
through

the
leaves
and
be
pulled
inside
the
building
through
the
vents
or
the
operable

158

windows
for
natural
ventilation.
The
software
used
for
this
study
was
Autodesk
CFD

Simulation
2013.
The
initial
wind
speed
was
set
at
a
typical
air
velocity
for
Los

Angeles
at
1
m/s.
The
following
figures
(C-‐4,
C-‐5,
C-‐6)
illustrate
the
results
of
the

simulation.

Figure
C-‐4:
CFD
Simulation
Results
for
horizontal
Shelves,
Depth
72"

Figure
C-‐5:
CFD
Simulation
Results
for
horizontal
shelves
equally
spaced,
Depth
72"

159

Figure
C-‐6:
CFD
Simulation
Results
for
vertical
panels
18"x18"

The
simulation
results
showed
that
the
horizontal
shelves,
especially
when
equally

spaced
present
a
better
potential
as
a
filtration
mechanism,
as
wind
velocity

increases
when
it
is
passing
through
the
vegetated
surfaces.
The
foliage
of
the

plants,
through
phytofiltration,
will
then
remove
an
amount
of
airborne
particles

and
subsequently
the
air
will
be
pulled
inside
the
building,
either
through
the

operable
window
or
the
vent.

C.2
DAYLIGHT
STUDY

Another
important
aspect
for
the
system
to
be
applicable
is
the
amount
of
daylight

that
it
allows
to
reach
the
interior,
as
well
as,
for
the
shelves
configurations,
the

amount
of
daylight
reaching
the
back
of
the
shelves
for
the
plants
to
survive.
The

simulations
were
performed
with
the
daylight
analysis
tool
of
Autodesk
3ds
Max

2013,
for
a
south-‐facing
facade.
The
study
was
performed
for
Los
Angeles
and
the

days
and
hours
that
the
simulations
were
performed
for,
were
the
21
st

of
June
and

21
st

of
December,
12pm,
1pm,
2pm
and
3pm
respectively.

160

Figure
C-‐7:
Comparative
interior
pseudo-‐color
rendering
for
06/21,
12p.m.

Figure
C-‐8:
Comparative
interior
pseudo-‐color
rendering
for
06/21,
1p.m.

Figure
C-‐9:
Comparative
interior
pseudo-‐color
rendering
for
06/21,
2p.m.

161

Figure
C-‐10:
Comparative
interior
pseudo-‐color
rendering
for
06/21,
3p.m.

Figure
C-‐11:
Comparative
interior
pseudo-‐color
rendering
for
12/21,
12p.m.

Figure
C-‐12:
Comparative
interior
pseudo-‐color
rendering
for
12/21,
1p.m.

162

Figure
C-‐13:
Comparative
interior
pseudo-‐color
rendering
for
12/21,
2p.m.

Figure
C-‐14:
Comparative
interior
pseudo-‐color
rendering
for
12/21,
3p.m.

The
daylight
study
for
the
interior
showed
that
the
vertical
panels
configuration
did

not
provide
any
shading
at
all
for
the
most
of
the
hours
tested.
The
horizontal

shelves
were
a
better
solution,
but
there
were
times
that
there
was
noticeable
glare

on
the
floor
and
walls
of
the
interior.
The
equally
spaced
shelves
proved
to
be
a

better
solution,
as
they
provided
both
shading
and
uniform
ambient
light,
adequate

for
workspaces,
about
400-‐600
lux.

Lastly,
an
important
factor
would
also
be
the
sun
light
reaching
the
back
of
those

shelves
and
if
it
would
be
adequate
for
the
selected
plant
species
survival.

163

Figure
C-‐15:
Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
06/12,
12p.m.

Figure
C-‐16:
Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
06/12,
1p.m.

164

Figure
C-‐17:

Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
06/12,
2p.m.

Figure
C-‐18:
Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
06/12,
3p.m.

165

Figure
C-‐19:
Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
12/12,
12p.m.

Figure
C-‐20:
Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
12/12,
1p.m.

166

Figure
C-‐21:
Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
12/12,
2p.m.

Figure
C-‐22:
Daylight
on
a
point
grid
on
a
horizontal
shelf,
for
06/12,
3p.m.

The
analysis
showed
that
even
though
there
was
some
sun
light
reaching
the
back
of

the
shelves,
it
was
not
adequate
for
the
survival
of
the
specific
species.
This
should

be
taken
into
consideration
during
the
plant
species
selection
of
a
future
application.

Asset Metadata

Creator Papaioannou, Ioli (author)

Core Title Vegetated facades as environmental control systems: filtering fine particulate matter (PM2.5) for improving indoor air quality

Contributor Electronically uploaded by the author (provenance)

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Publication Date 05/13/2013

Defense Date 03/15/2013

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag fine particulate matter,indoor air quality,OAI-PMH Harvest,phytofiltration,phytoremediation,PM2.5,vegetated facades

Format application/pdf (imt)

Language English

Advisor Noble, Douglas (committee chair), Borden, Gail Peter (committee member), Getov, Pavel (committee member), Konis, Kyle (committee member)

Creator Email ioni.papaioannou@gmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c3-255369

Unique identifier UC11293985

Identifier etd-Papaioanno-1688.pdf (filename),usctheses-c3-255369 (legacy record id)

Legacy Identifier etd-Papaioanno-1688.pdf

Dmrecord 255369

Document Type Thesis

Format application/pdf (imt)

Rights Papaioannou, Ioli

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the a...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus MC 2810, 3434 South Grand Avenue, 2nd Floor, Los Angeles, California 90089-2810, USA

Abstract (if available)

Abstract Air pollution is a problem present in the majority of the built environments. Ambient air pollution is consisted by many different pollutants which, depending on their concentration in the air, can have a severe impact on human health with long-term implications, and they can also deteriorate the surfaces of the buildings they come in contact with. Fine Particulate Matter (PM2.5) is amongst them. It is a pollutant that tends to exceed the allowable levels and that can have a severe impact on human health, as it is able to penetrate deep into the human respiratory system. Ambient air pollution is directly connected with Indoor Air Quality through infiltration and ventilation. In order to ensure good Indoor Air Quality and user comfort, the air introduced indoors needs to comply with specific standards. Air-pollution control doesn’t address the issue of pollutants already in the atmosphere, and for reducing those other filtration methods need to be applied. These practices can be energy consuming, especially when there is not proper maintenance, and sometimes even not as effective as expected. Bioremediation is a procedure based on biological processes, for filtering pollutants from air, soil or water, using living organisms. Phytoremediation is the specific process of filtering pollutants through the metabolism of plants. The use of vegetation on facades is being increased due to their many benefits for the building (shading, insulation). Since the building envelope is the part of the building that is in constant contact with the ambient air, the question that rises is whether a vegetated façade can be used as a filtration medium for ambient and indoor air. For testing this hypothesis, an experimental method was required to be developed, based on the testing method of conventional filters, to determine whether the process of phytofiltration, a form of phytoremediation, can provide efficient filtration for a specific pollutant, Particulate Matter 2.5.