Somerset County Average 2002 NATA Modeled Air Concentrations Compared to Health Benchmarks
Pollutant
Modeled
Air Concentration (ug/m3)
Health
Benchmark (ug/m3)
Risk
Ratio
%
Contribution from
Major Sources
Area
Sources
On-road
Mobile Sources
Nonroad
Mobile Sources
Background
Acetaldehyde
2
0.45
4
0.02%
3%
37%
8%
52%
Acrolein
0.07
0.020
4
0.1%
10%
69%
21%
0%
Arsenic Compounds
0.0004
0.00023
1.9
3%
7%
6%
5%
79%
Benzene
1
0.13
11
1%
12%
36%
13%
38%
1,3-Butadiene
0.1
0.033
3
0.4%
0.009%
36%
23%
41%
Cadmium Compounds
0.00009
0.00024
0.4
8%
28%
0%
1%
63%
Carbon Tetrachloride
0.6
0.067
9
0.0006%
0.08%
0%
0%
99.9%
Chloroform
0.1
0.043
2
0.4%
39%
0%
0%
61%
Chromium (hexavalent form)
0.0002
0.000083
2
42%
5%
5%
1%
47%
1,4-Dichlorobenzene
0.09
0.091
1
0.2%
47%
0%
0%
53%
1,3-Dichloropropene
0.08
0.25
0.3
0.00002%
100%
0%
0%
0%
Diesel Particulate Matter
1
0.0033
415
0%
0%
31%
69%
*
Ethylbenzene
0.4
0.4
0.9
1%
13%
55%
31%
0%
Ethylene Oxide
0.009
0.011
0.8
3%
8%
0%
0%
89%
Formaldehyde
2
0.077
25
0.1%
2%
22%
10%
66%
Methyl Chloride
1
0.56
2
0.02%
0.4%
0%
0%
99.6%
Methyl tert-butyl ether
2
3.8
0.5
0.3%
14%
34%
52%
0%
Naphthalene
0.08
0.029
3
3%
43%
13%
3%
38%
PAH/POM
0.01
0.0075
1.3
3%
77%
12%
8%
0%
Perchloroethylene
0.1
0.17
0.8
1%
48%
0%
0%
51%
1,1,2-Trichloroethane
1.2E-6
0.063
2.0E-5
0.00004%
100%
0%
0%
0%
Chemicals with risk ratios greater than or equal to 1 are
in bold.
Risk Ratios in italics are based on noncarcinogenic effects.
The symbol ug/m3 is micrograms per cubic meter,
the amount (in micrograms) of a chemical in a cubic
meter of air. This is also known as a concentration.
* For diesel particulate matter, onroad and nonroad
concentrations include a model-estimated background
concentration.
