Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris,...
-
Upload
margaretmargaret-jones -
Category
Documents
-
view
244 -
download
5
Transcript of Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris,...
![Page 1: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/1.jpg)
Influence of Attached Influence of Attached Garages on Indoor Garages on Indoor
VOC Concentrations in VOC Concentrations in Anchorage HomesAnchorage Homes
Stephen S. Morris, P.E.Stephen S. Morris, P.E.Municipality of AnchorageMunicipality of Anchorage
Department of Health and Human ServicesDepartment of Health and Human Services
![Page 2: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/2.jpg)
AcknowledgementsAcknowledgementsAnne Schlapia, Matt Stichick and Larry Taylor – MOA DHHSAnne Schlapia, Matt Stichick and Larry Taylor – MOA DHHS
John Freeman, Phil Kaluza, Ginny Moore – ABSNJohn Freeman, Phil Kaluza, Ginny Moore – ABSN
Sally Liu, Tim Gould, Dave Hardie and Timothy Ting Sally Liu, Tim Gould, Dave Hardie and Timothy Ting University of WashingtonUniversity of Washington
![Page 3: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/3.jpg)
BackgroundBackground
![Page 4: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/4.jpg)
A previous Anchorage study A previous Anchorage study sparked interest in a further sparked interest in a further
investigation of the influence of investigation of the influence of attached garages on air quality attached garages on air quality
inside Anchorage homes.inside Anchorage homes.
![Page 5: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/5.jpg)
Architectural, Behavioral, and Environmental Factors Associated with
Indoor VOCs in Anchorage Homes (1995)
• Sampled 137 homes for BETX between December Sampled 137 homes for BETX between December 1994 and February 1996 1994 and February 1996
• Summa canisters deployed in living space of homes Summa canisters deployed in living space of homes for 24 hoursfor 24 hours
• Documented architectural, behavioral and Documented architectural, behavioral and environmental characteristics of each home sampledenvironmental characteristics of each home sampled
![Page 6: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/6.jpg)
The most important factor influencing [benzene] and other BTEX compounds
was the presence of an attached garage.
• Cigarette smoking was not an important factor in determining benzene concentration in living space of the home.
• The presence of an attached garage was the single most important variable associated with elevated benzene inside the home.
![Page 7: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/7.jpg)
Comparison of Mean Benzene Concentrations in Single Family Homes 1994-1996 Anchorage Study
18.0
6.8
3.2
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
garagewith parked cars
N = 46
garagew/o parked cars
N = 16
no attached garageN = 14
[ben
zene
] pp
b
![Page 8: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/8.jpg)
Data suggested that Data suggested that attached garages increase attached garages increase
in-home exposure to benzene in-home exposure to benzene five-fold. five-fold.
Incremental increase in lifetime Incremental increase in lifetime exposure cancer risk was exposure cancer risk was
approximately approximately 1 in 6,000.1 in 6,000.
![Page 9: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/9.jpg)
Benzene content (3.9%) and volatility Benzene content (3.9%) and volatility of Alaska gasoline is higher thanof Alaska gasoline is higher than
most of the U.S. most of the U.S.
![Page 10: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/10.jpg)
We wanted to explore the We wanted to explore the mechanisms responsible for elevated mechanisms responsible for elevated
benzene in homes with attached benzene in homes with attached garages.garages.
![Page 11: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/11.jpg)
Study ObjectivesStudy Objectives Measure VOC concentrations in a representative sample Measure VOC concentrations in a representative sample
of 50 Anchorage homes with attached garages to assess of 50 Anchorage homes with attached garages to assess personal exposures.personal exposures.
Measure garage to house air infiltration rates. Measure garage to house air infiltration rates. Determine architectural / mechanical factors affecting the Determine architectural / mechanical factors affecting the amount of air entering house from the garage.amount of air entering house from the garage.
Identify possible strategies for reducing in-home VOC Identify possible strategies for reducing in-home VOC exposures through modification of architectural features, exposures through modification of architectural features, mechanical systems and/or modification of personal mechanical systems and/or modification of personal behaviors. behaviors.
![Page 12: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/12.jpg)
How much garage air infiltrates How much garage air infiltrates into the home and what are the into the home and what are the responsible mechanisms?responsible mechanisms?
How high are benzene and other How high are benzene and other VOCs inside the garage and what VOCs inside the garage and what sources are responsible?sources are responsible?
![Page 13: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/13.jpg)
We narrowed study scope to include non-smoking, detached single family
homes with attached garages only.
• Simplified analysis of air exchange rates.Simplified analysis of air exchange rates.
• Eliminated other possible confounding variables.Eliminated other possible confounding variables.
• Confined sampling to winter season when previous study Confined sampling to winter season when previous study showed VOC concentrations were highest.showed VOC concentrations were highest.
![Page 14: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/14.jpg)
House selectionHouse selection
![Page 15: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/15.jpg)
A representative sample of A representative sample of Anchorage homes was selected for Anchorage homes was selected for
sampling.sampling.
Used Anchorage municipal property tax Used Anchorage municipal property tax database to characterize housing stock by age database to characterize housing stock by age and square footage.and square footage.
Selected proportional number of houses in each Selected proportional number of houses in each sampling bin.sampling bin.
![Page 16: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/16.jpg)
Pre 1960 1960-1969 1970-1979 1980-1989 1990-2003 Grand Total
Less Than 1,200 SF 1.71% 1.52% 1.61% 1.99% 0.30% 7.13%1200-1799 SF 1.28% 2.70% 6.60% 9.62% 6.81% 27.02%
1,800-2,499 SF 1.06% 4.98% 15.55% 10.00% 12.27% 43.86%2,500-4,999 SF 0.73% 2.06% 6.07% 5.67% 6.51% 21.03%
5,000 & Greater SF 0.02% 0.04% 0.19% 0.27% 0.43% 0.96%
Grand Total 4.80% 11.30% 30.02% 27.56% 26.32% 100.00%
Pre 1960 1960-1969 1970-1979 1980-1989 1990-2003 Grand Total
Less Than 1,200 SF 1 1 1 1 0 41200-1799 SF 1 1 3 5 3 14
1,800-2,499 SF 1 2 8 5 6 222,500-4,999 SF 0 1 3 3 3 11
5,000 & Greater SF 0 0 0 0 0 0Grand Total 2 6 15 14 13 50
Age and size distribution of detached single family homes with attached garages in Anchorage.
Resultant sampling profile (50 home target)
![Page 17: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/17.jpg)
Tracer gases were used to Tracer gases were used to estimate air exchange rates estimate air exchange rates between garage and house.between garage and house.
![Page 18: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/18.jpg)
A PMCH tracer gas source emitter was deployed in each house and a PDCH source in each garage. The emission rate of each source was known.
PMCH
PDCHhouse
garage
![Page 19: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/19.jpg)
Capillary absorption tubes (CATs) were deployed in the house and garage to measure concentrations of PMCH and PDCH over a 24-hour period.
PMCH
PDCHCAT C
AT
![Page 20: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/20.jpg)
Mass balance approach was used to compute air exchange
rates between garage and house, house and outside, and
garage and outside.
![Page 21: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/21.jpg)
Four simultaneous equations were developed to estimate 4 unknown flows from measured [PMCH] and [PDCH] and the known emission rates of the two tracer gases.
QGA
QGL
QLG
QLA
PMCH
PDCH
Simultaneous equations could be solved and flow rates Simultaneous equations could be solved and flow rates QQGLGL, Q, QGAGA, Q, QLGLG, and Q, and QLALA could be computed for each house. could be computed for each house.
![Page 22: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/22.jpg)
The proportion of air in the house coming from The proportion of air in the house coming from the garage could be easily derived.the garage could be easily derived.
Proportion of house air coming from garage =
QGL/(QGL + QAL)
PMCH
PDCH
QAL
QGL
![Page 23: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/23.jpg)
VOC sampling methodologyVOC sampling methodology
![Page 24: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/24.jpg)
ATD tubes were ATD tubes were used to collect VOC used to collect VOC samples in the samples in the house and garage.house and garage.
Samplers were Samplers were deployed in active deployed in active living space in living space in home, typically in home, typically in living room.living room.
![Page 25: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/25.jpg)
![Page 26: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/26.jpg)
Ambient CO measurements were used to estimate outdoor concentrations of BTEX and butadiene.
Relationship Between Outdoor [CO] and [benzene]
y = 1.7858x + 1.6288
R2 = 0.5882
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Outdoor [CO] ppm
Ou
tdo
or
[be
nze
ne
] p
pb
![Page 27: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/27.jpg)
VOC resultsVOC results
![Page 28: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/28.jpg)
Summary of In-house VOC ConcentrationsSummary of In-house VOC Concentrations
N mean median max
1,3-butadiene 46 0.73 0.44 6.26
benzene 45 7.60 5.16 35.49
carbon tetrachloride 46 0.08 0.09 0.13
chlorobenzene 46 0.14 0.09 0.62
ethylbenzene 46 2.51 1.65 9.34
methylene chloride 46 2.79 0.35 73.16
napthalene 46 0.14 0.08 1.20
o-xylene 46 2.98 2.15 11.21
toluene 46 18.89 12.91 81.73
trichloroethene 44 0.03 0.02 0.49
m,p-xylene 46 6.92 5.19 33.78
![Page 29: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/29.jpg)
Distribution of Benzene Concentrations Inside Homes with Attached Garages
22
12
6
21
0
2
0
5
10
15
20
25
0 to 5 ppb
5 to 10 ppb
10 to 15 ppb
15 to 20 ppb
20 to 25 ppb
25 to 30 ppb
>30 ppb
Nu
mb
er o
f H
om
es
![Page 30: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/30.jpg)
For benzene and other BTEX compounds, mean For benzene and other BTEX compounds, mean concentrations in the house were approximately concentrations in the house were approximately
5 times higher than outside.5 times higher than outside.
Garage concentrations were 10 to 15 times Garage concentrations were 10 to 15 times higher than outside.higher than outside.
![Page 31: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/31.jpg)
Mean Benzene
7.60
26.08
1.66
0.00
5.00
10.00
15.00
20.00
25.00
30.00
House Garage Outdoor
ppb
![Page 32: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/32.jpg)
Toluene
18.89
61.35
5.42
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
House Garage Outdoor
o-Xylene
2.98
8.50
0.72
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
House Garage Outdoor
Ethylbenzene
2.51
6.51
0.46
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
House Garage Outdoor
m,p- Xylene
6.92
21.82
1.44
0.00
5.00
10.00
15.00
20.00
25.00
House Garage Outdoor
![Page 33: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/33.jpg)
Data Analysis and Data Analysis and DiscussionDiscussion
![Page 34: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/34.jpg)
Garage to house infiltration rates varied Garage to house infiltration rates varied considerably among homes sampled.considerably among homes sampled.
Homes with forced air furnaces in the Homes with forced air furnaces in the garage had higher infiltration rates than garage had higher infiltration rates than
homes with other heating configurations.homes with other heating configurations.
![Page 35: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/35.jpg)
![Page 36: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/36.jpg)
Comparison of Median Infiltration RatesProportion of House Air Originating from Garage
36.7%
17.0%18.4%
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
Forced AirFurnace
in GarageN = 15
Forced AirFurnacein House
N = 5
HydronicN=11
![Page 37: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/37.jpg)
Although the [CO] in many garages was Although the [CO] in many garages was high immediately after vehicle start-ups, high immediately after vehicle start-ups,
exhaust emissions do not appear to be the exhaust emissions do not appear to be the primary source of VOCs in the garage.primary source of VOCs in the garage.
![Page 38: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/38.jpg)
House 30
0
10
20
30
40
50
11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 3 4 5 6 7 8 9
Hour of Day
[CO
]pp
m
House
Garage
Outside
![Page 39: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/39.jpg)
CO vs benzene in garage
R2 = 0.2729
0
20
40
60
80
100
120
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00
CO (ppm)
be
nze
ne
(p
pb
)
![Page 40: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/40.jpg)
There was a stronger relationship There was a stronger relationship between CO and butadiene between CO and butadiene
concentrations.concentrations.
![Page 41: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/41.jpg)
CO vs butadiene in garage
R2 = 0.4111
0
1
2
3
4
5
6
7
8
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00
CO (ppm)
bu
tad
ien
e (
pp
b)
![Page 42: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/42.jpg)
The data do not show a significant The data do not show a significant association between the benzene level in association between the benzene level in the garage and:the garage and:
The number of vehicles parked in The number of vehicles parked in the garage;the garage;
The age of the vehicles in the The age of the vehicles in the garage; orgarage; or
The number of trips originating from The number of trips originating from the garage.the garage.
![Page 43: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/43.jpg)
Evaporative emissions may be a Evaporative emissions may be a more important source than more important source than
exhaust emissions.exhaust emissions.
![Page 44: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/44.jpg)
![Page 45: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/45.jpg)
Comparison of Benzene Concentration in the Garage
32.3
7.6
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Garage Usedfor Gasoline
Equipment StorageN = 23
Garage Not Usedfor Gasoline
Equipment StorageN = 8
med
ian
[b
enze
ne]
p
pb
![Page 46: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/46.jpg)
Having an elevated level of Having an elevated level of benzene in the garage was a good benzene in the garage was a good
indicator that benzene levels in indicator that benzene levels in the house would also be high.the house would also be high.
![Page 47: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/47.jpg)
Garage Benzene vs. House Benzene
y = 0.2789x + 0.4748
R2 = 0.7291
0
5
10
15
20
25
30
35
40
0 20 40 60 80 100 120
measured benzene in garage
me
as
ure
d b
en
zen
e i
n h
ou
se
(p
pb
)
![Page 48: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/48.jpg)
The benzene concentration in the house could The benzene concentration in the house could be precisely predicted from the garage be precisely predicted from the garage
concentration if the air exchange rate between concentration if the air exchange rate between the garage and house was known.the garage and house was known.
![Page 49: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/49.jpg)
[benzeneL] =
[benzeneA] x QAL/(QGL + QAL) + [benzeneG] x QGL/(QAL + QGL)
PMCH
PDCH
QAL
QGL
[benzeneA]
[benzeneG]
[benzeneL]
?
![Page 50: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/50.jpg)
Computed vs. Measured House Benzene
y = 0.9224x + 0.6102R2 = 0.9563
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35 40
measured benzene in house
co
mp
ute
d b
en
zen
e i
n h
ou
se
(p
pb
)
![Page 51: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/51.jpg)
27% of air from garage
73% of air from outside
[benzene] = 1.4 ppb
[benzene] = 29.8 ppb
Outside air
garage[benzene] = 8.8 ppb
house
The “average” Anchorage house….
- benzene concentration is 6 times higher than outside
- 27% of air in the house comes from garage
- over 90% of benzene in house comes from the garage
![Page 52: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/52.jpg)
BTEX concentrations dropped considerably between BTEX concentrations dropped considerably between 1994-96 study and 2003-2004 study1994-96 study and 2003-2004 study
Comparison of In-home BTEX Concentrations1994-94 study vs. 2003-2004 study
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
Benzene Toluene Ethylbenzene m,p-Xylene o-Xylene
pp
b
1994-96 Study 2003-2004 Study
![Page 53: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/53.jpg)
Phase 2 – Evaluation of Phase 2 – Evaluation of Mitigation StrategiesMitigation Strategies
![Page 54: Influence of Attached Garages on Indoor VOC Concentrations in Anchorage Homes Stephen S. Morris, P.E. Municipality of Anchorage Department of Health and.](https://reader033.fdocuments.in/reader033/viewer/2022061600/56649e795503460f94b78a49/html5/thumbnails/54.jpg)
Candidate StrategiesCandidate Strategies
Remove gasoline-fueled equipment from Remove gasoline-fueled equipment from garage.garage.
Modify forced air systems placed in Modify forced air systems placed in garages to reduce air infiltrationgarages to reduce air infiltration
Ventilate garage to reduce VOC Ventilate garage to reduce VOC concentrationsconcentrations
Lower benzene content in gasolineLower benzene content in gasoline