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Indoor Air Quality Evaluation



Media-specific health comparison values are contaminant concentrations in specific media (i.e., soil, water and air) used to select contaminants of concern for further evaluation. If the concentration of a chemical exceeds a health comparison value, it does not mean that a public health threat exists but rather signifies that the chemical be further evaluated.

The health comparison values used in this public health assessment include environmental media evaluation guidelines (EMEGs) and cancer risk evaluation guidelines (CREGs). EPA Region IX and Region III risk based concentrations were also used when no other comparison values were available.

EMEGs are media-specific health comparison values derived from minimal risk levels (MRLs) presented in ATSDR Toxicological Profiles. MRLs are estimates of daily exposure of a human to a chemical that is likely to be without an appreciable noncancer risk over a specified duration of exposure. CREGs are estimated media specific contaminant concentrations that are anticipated to result in one excess cancer risk in one million persons exposed over a lifetime. CREGs are derived from EPA's cancer slope factors (CSFs), also known as cancer potency factors. CSFs are cancer potency estimates derived for chemicals shown to be carcinogenic in animals or humans.

EPA Region IX and Region III conservative risk based screening concentrations are derived for carcinogenic and noncarcinogenic compounds using CSFs and RfDs, respectively. RfDs are estimates of daily exposure of a human to a chemical that is likely to be without an appreciable noncancer risk over a specified duration of exposure.


Table C-1:

EPA August 2000 Indoor Air Sampling Results
Contaminant Residence 2
1st Floor
Business 2
1,1,1-trichloroethane NA NA
1,1,2,2-tetrachloroethane 0.14 0.07
1,1,2-trichloroethane 0.49 0.05
1,1-dichloroethane 59.96 45.12
1,1-dichloroethene 0.71 0.87
1,2,4-trichlorobenzene 0.22 0.15
1,2-dichloroethane 0.81 0.69
1,2-dichlorobenzene 0.12 0.06
1,2-dichloropropane 6.47 1.34
1,3-butadiene 0.42 0.11
1,3-dichlorobenzene 0.12 0.06
1,4-dichlorobenzene 16.71 35.70
2-butanone NA NA
acetone NA NA
benzene 29.95 6.39
bromomethane 3.79 3.48
cis-1,2-dichloroethene 10.82 16.49
cis-1,3-dichloropropene 0.54 0.27
carbon tetrachloride 0.69 1.70
chlorobenzene 37.09 8.97
chloroform 3.32 0.98
chloromethane NA NA
ethylbenzene 2.55 7.79
freon-11 15.16 11.16
freon-113 7.58 56.28
freon-12 13.30 3.84
m,p-xylene 20.97 30.73
methylene chloride 2.99 0.28
o-xylene 3.30 9.80
tetrachloroethene 25.22 10.17
styrene NA 2.84
trans-1,2-dichloroethene NA NA
trichloroethene 3.06 12.52
toluene 349.98 23.81
vinyl chloride 1.05 NA


Table D-1:

Cancer Risk and Noncancer Hazards - COPCs
Contaminant Maximum Conc (ug/m3) Inhalation Unit Risk (per ug/m3) Slope Factor (mg/day/kg)-1 RfC (mg/m3) RfD (mg/kg-day) Cancer Risk Max Hazard Quotient Max
1,1,2,2-tetrachlorethane 1.61 5.8e-05 9.3e-05
1,1-dichloroethene 1.2 2.0e-01 6.0e-03
1,1,2-trichloroethane 2.2 1.6e-05 4.0e-03 3.5e-05 3.0e-01
1,2-dichloroethane 5.91 2.6e-05 1.5e-04
1,2-dichloropropane 1.02 4.0e-03 2.6e-01
benzene 10.2 7.8e-06 8.0e-05
carbon tetrachloride 1.0 1.5e-05 7.0e-04 1.5e-05 7.9e-01
cis-1,3-dichloropropene 0.77 4.0e-06 2.0e-02 3.1e-06 3.9e-02
chloroform 2.2 1.0e-02 6.3e-06
ethylbenzene 5.2 3.9e-03 2.9e-01 5.8e-06 9.9e-03
methylene chloride 330 4.7e-07 6.0e-02 1.6e-04 3.0e+00
tetrachloroethene 6.44 2.0e-03 1.0e-02 3.7e-06 3.6e-01
trichloroethene 17.19 4.0e-01 4.0e-02 2.0e-03 4.3e-01
vinyl chloride 0.74 8.8e-06 1.0e-01 6.5e-06 7.4e-03
Total Risk for Chemicals with Indoor Air Literature Values Cancer Risk 2.5e-03
Hazard Index 5.2e+00

Table D-2:

Cancer Risk and Noncancer Hazards - Indoor Air Literature Values
Contaminant Maximum Conc (ug/m3) Inhalation Unit Risk (per ug/m3) Slope Factor (mg/day-/kg)-1 RfC (mg/m3) RfD (mg/kg-day) Cancer Risk Max Hazard Quotient Max
1,1,2,2-tetrachlorethane 0.1 5.8e-05 5.8e-06
1,1-dichloroethene 2.0e-01
1,1,2-trichloroethane 1.8 1.6e-05 4.0e-03 2.9e-05 2.5e-01
1,2-dichloroethane 0.14 2.6e-05 3.6e-06
1,2-dichloropropane 0.01 4.0e-03 2.5e-03
benzene 10 7.8e-06 7.8e-05
carbon tetrachloride 2.5 1.5e-05 7.0e-04 3.8e-05 2.0e+00
cis-1,3-dichloropropene 4.0e-06 2.0e-02
chloroform 0.5 1.0e-02 1.4e-06
ethylbenzene 4.8 3.9e-03 2.9e-01 5.3e-06 9.2e-03
methylene chloride 6 4.7e-07 6.0e-02 2.8e-06 5.5e-02
tetrachloroethene 5 2.0e-03 1.0e-02 2.9e-06 2.8e-01
trichloroethene 0.7 4.0e-01 4.0e-02 8.0e-05 1.8e-02
vinyl chloride 8.8e-06 1.0e-01
Total Risk for Chemicals with Indoor Air Literature Values Cancer Risk 2.5e-04
Hazard Index 2.6e+00

Table D-3:

Cancer and Noncancer Risks for March 2001 Maximum and Average Concentrations
IUR Indoor Air
(per Slope Factor RfC RfD Max Conc. Cancer Avg Conc Cancer
Chemical ug/m3) (mg/kg/day)-1 (mg/m3) (mg/kg-day) (ug/m3) Risk HQ (ug/m3)
Risk HQ
1,1,1-trichloroethane 120 13.6
1,1,2,2-tetrachloroethane 5.8E-05 0.3 1.7E-05 0.2 1.2E-05
1,1,2-trichloroethane 1.6E-05 4.0E-03 2.2 3.5E-05 3.0E-01 0.4 6.4E-06 5.5E-02
1,1-dichloroethane 1.6E-06 1.0E-01 23.1 3.7E-05 2.3E-01 2.5 4.0E-06 2.5E-02
1,1-dichloroethene 2.0E-01 1.2 6.0E-03 0.2 1.0E-03
1,2,4-trichlorobenzene 1.0E-02 0.4 2.2E-02 0.2 1.1E-02
1,2-dichloroethane 2.6E-05 0.8 2.1E-05 0.2 5.2E-06
1,2-dichlorobenzene 9.0E-02 1.6 9.8E-03 0.3 1.8E-03
1,2-dichloropropane 4.0E-03 0.2 5.0E-02 0.1 2.5E-02
1,3-butadiene 2.0E-03 NA NA
1,3-dichlorobenzene 0.3 0.2
1,4-dichlorobenzene 1.10E-05 8.0E-01 144.2 1.6E-03 1.8E-01 15.9 1.7E-04 2.0E-02
2-butanone 1.0E+00 13 1.3E-02 5.7 5.7E-03
acetone 1.0E-01 498.6 2.8E+00 88.7 4.9E-01
benzene 7.8E-06 9.6 7.5E-05 3.2 2.5E-05
bromomethane 5.0E-03 0.2 4.0E-02 0.1 2.0E-02
cis-1,2-dichloroethene 16.6 1.8
cis-1,3-dichloropropene 4.0E-06 2.0E-02 0.2 8.0E-07 1.0E-02 0.1 4.0E-07 5.0E-03
carbon tetrachloride 1.5E-05 7.0E-04 0.8 1.2E-05 6.3E-01 0.6 9.0E-06 4.7E-01
chlorobenzene 2.0E-02 0.2 5.5E-03 0.1 2.8E-03
chloroform 1.0E-02 1.7 4.9E-06 0.5 1.4E-06
chloromethane 11.6 2.3
ethylbenzene 3.9E-03 2.9E-01 6.1 6.8E-06 1.2E-02 2.2 2.5E-06 4.2E-03
freon-11 3.0E-01 46.1 8.5E-02 11.5 2.1E-02
freon-113 71.2 7.9
freon-12 2.0E-01 33.6 9.3E-02 9.8 2.7E-02
m,p-xylene 2.0E+00 17.4 4.8E-03 6.9 1.9E-03
methylene chloride 4.7E-07 6.0E-02 38.2 1.8E-05 3.5E-01 10.5 4.9E-06 9.7E-02
o-xylene 2.0E+00 5.6 1.5E-03 2.6 7.2E-04
tetrachloroethene 2.0E-03 1.0E-02 2 1.1E-06 1.1E-01 0.7 4.0E-07 3.9E-02
styrene 1.0E+00 4.7 4.7E-03 1.4 1.4E-03
trans-1,2 dichloroethene 2.0E-02 0.5 1.4E-02 0.1 2.8E-03
trichloroethene 4.0E-01 4.0E-02 11.3 1.3E-03 2.8E-01 3.3 3.8E-04 8.3E-02
toluene 4.0E-01 33.9 8.5E-02 13.8 3.5E-02
vinyl chloride 8.8E-06 1.0E-01 0.1 8.8E-07 1.0E-03 0.1 8.8E-07 1.0E-03
Total Risk-Max Conc Total Risk-Avg Conc
Cancer 3.1E-03 Cancer 6.2E-04
HQ 5.3E+00 HQ 1.5E+00


This Health Consultation was prepared by the Washington State Department of Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health consultation was begun.

Debra Gable
Technical Project Officer,

The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.

Roberta Erlwein
Section Chief,

Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
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