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Produced by and for the Hot Science - Cool Talks Outreach Lecture Series of the Environmental Science Institute. We request that the use of any of these materials include an acknowledgement of Dr. Richard Corsi and the Hot Science - Cool Talks Outreach Lecture Series of the Environmental Science Institute of the University of
Texas at Austin. We hope you find these materials educational and enjoyable.
by Dr. Richard CorsiHot Science - Cool Talks Volume 56
Is Your House Killing You?
Co-sponsored by the McDonald Observatory and Department of Astronomy Board of Visitors
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 & EngineeringDepartment 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
050
100150200250300350
1920 1940 1960 1980 2000
YearBill
ion
kg/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
ventoutsideinside Q
ECC
ventilation (Qvent)
emissions (E)
outdoor pollution (Coutside)
control (η x Qcontrol)
vent
control
ventoutside
inside
QE
C
C
1
Qvent Qvent
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
ProfessorJeffrey Siegel
Clean Air Delivery Rate (CADR)C
lean
Air
Del
iver
y R
ate
(m3 /
hr)
Test Aerosol: Incense
vent
control
ventoutside
inside
QE
C
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 qualitycompare 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 pesticides16 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
ventoutsideinside Q
ECC
A few examplesNow let’s examine just a few examples
(some might surprise you!)
Scented candles
Emission Factor (g/g)Scented 1200Unscented 20
Scented Candles
Average Concentrations of VOCs
00.050.1
0.150.2
0.250.3
0.350.4
0.450.5
Co
nce
ntr
atio
n (
g/m
3)
ScentedUnscented
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 (m
g/h
r)
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 CRFOR: formaldehydeDCB: p-dichlorobenzene
ACE: acetaldehydeCHL: chloroformBZ: benzene
STY: styreneMCL: methylene chlorideTCE: trichloroethylene
CT: carbon tetrachlorideEBZ: ethylbenzeneTET: 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 WashingMachine
Shower Dishwasher
Av
era
ge
Tra
ns
fer
Eff
icie
nc
y (
%)
AcetoneEthyl AcetateTolueneEthylbenzeneCyclohexane
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
ProfessorJeffrey Siegel
Ion Generators: Ozone Emission Rates
Pers. data
Ion Generator
Ozo
ne
Em
issi
on
s (m
g/h
r)
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 CO
OO
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
R3C C
OO
OO3 +R1
R4R2
R3
C CR1
R4R2
R3C C
OO
OO3 +R1
R4R2
R3
C CR1
R4R2
R3
C CR1
R4R2
R3C C
OO
O
Example: Solid Air Freshener
# P
artic
les
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 Experiments
λ = 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 ResultsParticle 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