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Dr. Richard Corsi
October 10, 2008
Is Your House Killing You?
# 56
Title SlideIs Your Home Killing You?Indoor Air Quality: A Time for Recognition
Richard L. Corsi, Ph.D., PEE.C.H. Bantel Professor for Professional Practice
Director – Program on Indoor Environmental Science & Engineering
Department of Civil, Architectural and Environmental Engineering
When did indoor
air quality
problems begin?
http://kuroow.blox.pl/html
Situation Persists in Developing World
½ world’s population (> 3 B) relies
on coal and biomass for domestic
energy, and number is increasing!
• Used in simple stoves.
• Incomplete combustion.
• Often not ventilated.
• 2 – 2.8 million deaths/year
• 4% of global mortality
• 1 million childhood deaths/year
• Women: 2/3 w/ lung cancer
are non-smokers!© Ron Giling Panos Pictures
UN ITDG Briefings
Developed World - Evolution of IAQ
affordablehousinginstitute.orgwww.cdc.gov
• Demand for homes (end of WW II)
Demand for Ease of Life
• Wall-to-wall carpet
• Cleaners
• Air fresheners
• Pesticides
• Personal care products
• Much more
Global Production: Synthetic Organic Chemicals
0
50
100
150
200
250
300
350
1920 1940 1960 1980 2000
YearB
illi
on k
g/y
ear
Air Conditioning
• Energy crisis of 1970s (buildings ≈ 70%)
• Energy crisis of 21st century (buildings ≈ 40%)
• Advantageous to keep the outdoors out. Why?
• How: Seal up home, re-circulate conditioned air
Infrogmation
Building Blocks
vent
outsideinsideQ
ECC
ventilation (Qvent)
emissions (E)
outdoor pollution (Coutside)
control (η x Qcontrol)
vent
control
vent
outside
inside
Q
Q
Q
EC
C
1
QventQvent
E
Cinside
Coutside
Qcontrol
η x Qcontrol = CADR (clean air delivery rate)
Ion Generators
HEPA Filter
Ion Generator 3
Ion Generator 2Ion Generator 5
Ion Generator 4
Ion Generator 1
Professor
Jeffrey Siegel
Clean Air Delivery Rate (CADR)C
lea
n A
ir D
eliv
ery
Rate
(m
3/h
r) Test Aerosol: Incense
vent
control
vent
outside
inside
Q
Q
Q
EC
C
1
Particle Diameter (µm)
It’s Not Only In the Air!
“If truckloads of dust with the same concentration of toxic chemicals as
is found in most carpets were deposited outside, these locations would
be considered hazardous waste dumps”
Ott & Roberts, “Everyday Exposure to Toxic Pollutants,” Scientific American, 1998
• 360 mid-western homes (1992 – 1993)
• Pesticides and Polyaromatic Hydrocarbons
(PAHs; soot and parking lot sealant)
• DDT (toxic pesticide) in 25% of homes (banned in 1972!)
• PAH levels in > 50% of homes ……………
How much time do you spend indoors?How much time do you spend indoors?
Americans = Indoor Creatures
• Indoors 89%
• 18 hours indoors for every 1 outdoors
• 2/3 of time in home
• Transit 6%
• Outdoors 5%
Klepeis et al. 2001
How do risks from poor indoor air quality
compare with other environmental risks?
USEPA Risk Rankings
1. (tie) Worker exposure to chemicals
1. (tie) Indoor radon
3. Pesticide residue on foods
4. (tie) Indoor air pollutants (non-radon)
4. (tie) Consumer exposure to chemicals
(includes cleaning fluids, etc.)
6. Hazardous/toxic air pollutants
7. Depletion of stratospheric ozone
8. Hazardous waste sites (inactive)
9. Drinking water (radon and THMs)
10. Application of pesticides
16 others .. (including groundwater contamination at 21, criteria air pollutants at 22, etc.)
Risk of cancer/death - breathing
indoor air as high as 0.5 to 1%
(conventional risk assessment)
Corsi, Environ. Manager (2000)
http://www.epa.gov/oppt/rsei/index.html
Indoor pollution sourcesLet’s discuss some sources
(those things that emit pollution indoors)
Lots of images
vent
outsideinsideQ
ECC
A few examplesNow let’s examine just a few examples
(some might surprise you!)
Scented candles
Emission Factor (mg/g)
Scented 1200
Unscented 20
Scented Candles
Average Concentrations of VOCs
00.050.1
0.150.2
0.250.3
0.350.4
0.450.5
Benze
ne
Ethylbe
nzen
e
Styre
ne
Tolue
ne
1,2,
4-Trim
ethy
lben
zene
Xylen
es (a
ll isom
ers)
Co
ncen
trati
on
(m
g/m
3)
Scented
Unscented
Exposure to fine particulate matter (a heavily regulated outdoor air pollutant):
What is the outdoor source equivalent of burning a single candle in a home?
Every major industrial point source emitter, including all coal-fired power plants in the
State of Texas!
p-DCB = 1,4-Dichlorobenzene
• Molecular structure of p-
DCB
• Where does it come
from?
Average Emission Rates: 5 Day Test
1
10
100
1000
10000
closet freshener mothcase moth crystal toilet deodorizer
E (
mg/
hr)
Chamber Fume Hood Garment Bag Closet
closet freshener moth case moth crystal toilet deodorizer
Model: Buildup of Emissions (Concentration)
vs. Air Changes
Three product (super) user
Field Samples: Cancer Risk Estimates
CCR: cumulative CR
FOR: formaldehyde
DCB: p-dichlorobenzene
ACE: acetaldehyde
CHL: chloroform
BZ: benzene
STY: styrene
MCL: methylene chloride
TCE: trichloroethylene
CT: carbon tetrachloride
EBZ: ethylbenzene
TET: tetrachloroethylene
153
14
Hun et al. 2008
Toxic Air Contaminants
• Large computer manufacturer
• Clients getting sick when new computers arrive
• What is emitted?
48 toxic chemicals identified
75% decay within a few days
Personal Computers
Smell of apples?Smell of Apples?
Apple says that “… an unusual odor may be detected when a product has
been turned on and allowed to warm up to operating temperature. Typically,
the odor is detected when the product is new… In most cases the odor will
dissipate over a short period of time.“
Apple suggests that if the odor problem persists, that the machine be placed
in a well-ventilated room and allowed to operate over an "extended" period
of time (possibly 24-72 hours) or until the odor dissipates.
-- Applelinks Contributing Editor Charles W. Moore
“Sorry, Steve, But The G4 Stinks, And So Does My PowerBook”
"perhaps today's olfactory status symbol is the smell of scorching plastic."
-- Salon.com's Janelle Brown
Vaccuum cleanersVacuum Cleaners
• Previous tests on several vacuum cleaners
• Particle re-suspension by wheels on carpet
• Particles through collection device (bag, etc.)
• Particle emissions from motor
• 48 tests in 12 apartments in Austin
• Recall previous study related to toxic pollutants in carpet
• Those with dust allergies/asthma should leave during and following
vacuum events
Dishwashers & Washing Machines
Carlos Paes
• Detergents / bleaches with sodium hydrochloride
(“chlorine”, classified as hazardous)
• Experiments show large amounts of chloroform
• Dishwashers GREAT as chemical strippers
Lkayama
Major Appliances: How good are they at putting
toxic chemicals into the air?
0
10
20
30
40
50
60
70
80
90
100
Kitchen Sink Bathtub Washing
Machine
Shower Dishwasher
Av
era
ge
Tra
ns
fer
Eff
icie
nc
y (
%) Acetone
Ethyl Acetate
Toluene
Ethylbenzene
Cyclohexane
0.00
0.10
0.20
0.30
0.40
0.50
% I
nta
ke
ingestion inhalation dermal
SCENARIO 1
57%29%
5%
9%
0%
0%show er
laundry
dishw asher
toilets
cooking
w ash basins
Contributions to inhalation exposure
Exposure to Chloroform in Tap Water
50
40
30
20
10
00
Exposure to Chloroform w/ Reactions
0.00
0.20
0.40
0.60
0.80
% I
nta
ke
ingestion inhalation dermal
SCENARIO 2
80
60
40
20
00
Contributions to
inhalation exposure
22%
16%
59%
0%
0%
3% shower
laundry
dishwasher
toilets
cooking
wash basins
Contributions to
inhalation exposure
22%
16%
59%
0%
0%
3% shower
laundry
dishwasher
toilets
cooking
wash basins
Indoor OzoneIndoor Ozone
What are major sources of ozone indoors?
• Outdoor air
• Laser printers
• Photocopy machines
• Ion generating air purifiers
• Electrostatic precipitators
• Explicit ozone generators as air “purifiers”
Aris et al. 1993
Ion Generators
HEPA Filter
Ion Generator 3
Ion Generator 2Ion Generator 5
Ion Generator 4
Ion Generator 1
Professor
Jeffrey Siegel
Ion Generators: Ozone Emission Rates
Pers. data
Ion Generator
Ozo
ne E
mis
sio
ns (
mg
/hr)
Ozone in a Typical Residence
10 ppb increase in the previous week’s
ambient ozone concentration was associated
with a 0.52% increase in daily mortality --(Bell et al. 2004)
Explicit Ozone Generators
Nursery Air Purifier
“Give your baby healthy air. Make
baby’s nursery a healthy place, with our
stat-of-the-art purifier and ionizer! This
powerful little unit releases billions of
negative ions that effectively remove
allergens, bacteria, dust, and odors (all
of which are positively charged). Think
of invigorating mountain air… also rich
with negative ions. Wonderful for
respiratory systems that are still
developing. Purifies up to 200 square
feet, trapping particles as small as 100
microns. With a wipe-off, reusable
filter.”
Is your home a chemical reactor?
Is your home a chemical reactor?
Ozone + Unsaturated Organic Compounds
O3 +R1
R4R2
R3
C CR1
R4R2
R3
C C
OO
O
Many by-products are formed:
• Irritating and even toxic gases (e.g., formaldehyde)
• Particles
Sources of (C=C) – Numerous!
• Carpet (e.g., styrene)
• Cleaning products
• Polishes and waxes
• Air fresheners
• Personal care products (soaps, perfumes, etc.)
• Cooking oils
• Wood / plants
• Human skin oils (squalene)
O3 +R1
R4R2
R3
C CR1
R4R2
R3
C C
OO
OO3 +R1
R4R2
R3
C CR1
R4R2
R3
C C
OO
OO3 +R1
R4R2
R3
C C
R1
R4R2
R3
C CR1
R4R2
R3
C C
OO
O
Example: Solid Air Freshener
# P
art
icle
s
Time (min)
Particles released over time by size class
Sarwar et al. 2004
Is near head chemistry possible?
Perfumes and Colognes
• 25% of Americans use perfume or cologne daily
• 5% use perfume or cologne 3-5 × per day
• 3+ million “super users”
• Source composition:
• over 3,000 chemicals (terpenes, alcohols, etc.)
• loaded with C=C double bonds
• reactive – top notes, middle notes, base notes
• Odor thresholds: ≈ 100 – 1,000 × typical indoor
• typical indoor concentrations = < 1 to 10 ppb
Personal Reactive Clouds: Conceptual
O3
O3
O3
C=C
Product
Product
Product
Wisthaler et al. 2005
Product
Screening Experiments
O3 O3(meas)
VOC/ald
particles
T, RH, CO2
Screening
Experimentsλ = 1-2 min-1
~ 70 ppb
28 L
0
1,000
2,000
3,000
4,000
Perf 1 Perf 2 Perf 3 HS 1 HS 2Co
nc
en
tra
tio
n in
cre
as
e (
#/c
m3)
Experimental Results
Particle increase with product vs. without product (corrected for background)
Statistically significant
increase (α = 0.05)
perfumes hair sprays
What can you do?
• Become as educated as possible
• Educate as many others as possible
• Let your elected reps know of your concern
• Become a smart policymaker/engineer of your home
• The things you can do are too numerous for a slide
- avoid specific sources
- use selective ventilation
- use appropriate control devices (air purifiers)
Summary
• Indoor air quality is very important issue
– Greatest environmental health issue in U.S.!
• Affects everyone almost all of the time
• Great need for more public education
• Great need for more experts in field
• Great need for more research
– Miles behind other environmental issues
– US years/decades behind other countries
• University of Texas is a national leader in field
• And we have fun, too!
Questions
www.caee.utexas.edu/igert
IGERT: Indoor Environmental
Science & Engineering
The University of Texas
IGERT: Indoor Environmental
Science & Engineering
The University of Texas
Dr. Richard Corsi
Richard Corsi researches indoor air quality, including sources
and control of indoor air pollution and human exposure to indoor
toxic pollutants from dishwashers to paint and computers. He
recently completed a large study involving building disinfection
chemistry in the wake of anthrax attacks in 2001. He and his
research team have published over 230 journal/conference
papers and reports, and have been featured on The Nature of
Things, National Geographic, The Economist, BusinessWeek,
National Wildlife, Prevention, Men’s Health, and more. Corsi
earned his Ph.D. in civil engineering from the U.C. Davis in
1989 and joined the faculty of UT Austin in 1994.
