MERCER 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
<1%
4%
4%
2%
90%*
Acrolein
0.048
0.020
2.4
<1%
25%
12%
9%
54%*
Arsenic Compounds
0.00048
0.00023
2.1
5%
13%
4%
4%
74%
Benzene
1.0
0.13
7.7
<1%
12%
23%
11%
54%
1,3-Butadiene
0.074
0.033
2.2
0%
<1%
31%
15%
54%
Cadmium Compounds
0.00011
0.00024
0.4
5%
45%
0%
<1%
50%
Carbon Tetrachloride
0.61
0.067
9.1
0%
<1%
0%
0%
100%
Chloroform
0.13
0.043
3.1
<1%
56%
0%
0%
44%
Chromium (hexavalent form)
0.00014
0.000083
1.7
17%
10%
5%
<1%
68%
Cobalt Compounds
0.0000091
0.00011
0.08
100%
<1%
0%
0%
0%
1,4-Dichlorobenzene
0.11
0.091
1.2
<1%
26%
0%
0%
74%
1,3-Dichloropropene
0.11
0.25
0.4
0%
100%
0%
0%
0%
Diesel Particulate Matter
0.8
0.0033
244
0%
0%
54%
46%
0%
Ethylbenzene
0.18
0.4
0.4
1%
16%
49%
34%
0%
Ethylene Oxide
0.012
0.011
1
1%
33%
0%
0%
66%
Formaldehyde
1.9
0.077
25
<1%
3%
6%
4%
87%*
Methyl Chloride
1.2
0.56
2.2
0%
1%
0%
0%
99%
Naphthalene
0.098
0.029
3.4
1%
45%
21%
3%
30%
Nickel Compounds
0.00046
0.0021
0.2
42%
32%
4%
1%
21%
PAH/POM
0.014
0.0072**
1.9
<1%
88%
5%
7%
0%
Perchloroethylene
0.16
0.17
1
<1%
60%
0%
0%
40%
1,1,2-Trichloroethane
1.3E-6
0.063
2.1E-5
18%
82%
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.
