SOMERSET
COUNTY
SOMERSET County Average 2005 NATA Modeled Air Concentrations Compared to Health Benchmarks |
Pollutant |
Modeled
Air Concentration (ug/m3) |
Health
Benchmark (ug/m3) |
Risk
Ratio |
%
Contribution from |
Point Sources |
Nonpoint
Sources |
On-road
Mobile Sources |
Nonroad
Mobile Sources |
Background & Secondary |
Acetaldehyde |
1.8 |
0.45 |
3.9 |
0% |
3% |
4% |
2% |
91%* |
Acrolein |
0.044 |
0.020 |
2.2 |
<1% |
17% |
11% |
11% |
61%* |
Arsenic Compounds |
0.00043 |
0.00023 |
1.8 |
3% |
7% |
3% |
4% |
83% |
Benzene |
0.99 |
0.13 |
7.6 |
<1% |
10% |
22% |
13% |
55% |
1,3-Butadiene |
0.075 |
0.033 |
2.3 |
0% |
<1% |
29% |
18% |
53% |
Cadmium Compounds |
0.000086 |
0.00024 |
0.4 |
8% |
29% |
0% |
<1% |
63% |
Carbon Tetrachloride |
0.61 |
0.067 |
9.1 |
0% |
<1% |
0% |
0% |
100% |
Chloroform |
0.098 |
0.043 |
2.3 |
<1% |
39% |
0% |
0% |
61% |
Chromium (hexavalent form) |
0.00015 |
0.000083 |
1.8 |
24% |
5% |
4% |
1% |
66% |
Cobalt Compounds |
0.000029 |
0.00011 |
0.3 |
96% |
4% |
0% |
0% |
0% |
1,4-Dichlorobenzene |
0.088 |
0.091 |
0.9 |
<1% |
47% |
0% |
0% |
53% |
1,3-Dichloropropene |
0.079 |
0.25 |
0.3 |
0% |
100% |
0% |
0% |
0% |
Diesel Particulate Matter |
0.55 |
0.0033 |
167 |
0% |
0% |
49% |
51% |
0% |
Ethylbenzene |
0.19 |
0.4 |
0.5 |
1% |
23% |
40% |
36% |
0% |
Ethylene Oxide |
0.0088 |
0.011 |
0.8 |
2% |
8% |
0% |
0% |
90% |
Formaldehyde |
1.9 |
0.077 |
24 |
<1% |
2% |
5% |
5% |
88%* |
Methyl Chloride |
1.2 |
0.56 |
2.2 |
<1% |
<1% |
0% |
0% |
100% |
Naphthalene |
0.089 |
0.029 |
3.1 |
1% |
39% |
20% |
5% |
35% |
Nickel Compounds |
0.00042 |
0.0021 |
0.2 |
39% |
30% |
4% |
4% |
23% |
PAH/POM |
0.0094 |
0.0072** |
1.3 |
<1% |
82% |
6% |
12% |
0% |
Perchloroethylene |
0.13 |
0.17 |
0.7 |
<1% |
48% |
0% |
0% |
52% |
1,1,2-Trichloroethane |
1.4E-6 |
0.063 |
2.0E-5 |
66% |
34% |
0% |
0% |
0% |
|
Chemicals with risk ratios greater than or equal to 1 are
in bold.
Risk Ratios based on noncarcinogenic effects are in italics.
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. *Acetaldehyde, acrolein and formaldehyde concentration estimates include secondary formation, which is the process by which chemicals in the air are transformed into other chemicals.
**PAH/POM is "polycyclic aromatic hydrocarbons/polycyclic organic matter." These define a broad class of compounds. The chemicals making up this class were broken up into 8 groups based on toxicity, and each group was assigned a cancer-weighted toxicity estimate. 0.0072 ug/m3 is the health benchmark average across the 8 groups. |
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