UNION 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
2.3
0.45
5.1
<1%
5%
9%
4%
82%*
Acrolein
0.08
0.020
4
<1%
21%
18%
10%
51%*
Arsenic Compounds
0.00065
0.00023
2.8
2%
13%
7%
5%
73%
Benzene
2.1
0.13
16
1%
12%
32%
12%
43%
1,3-Butadiene
0.16
0.033
4.8
<1%
<1%
39%
15%
46%
Cadmium Compounds
0.00012
0.00024
0.5
8%
50%
0%
1%
41%
Carbon Tetrachloride
0.61
0.067
9.1
0%
<1%
0%
0%
100%
Chloroform
0.17
0.043
4
1%
50%
0%
0%
49%
Chromium (hexavalent form)
0.00048
0.000083
5.7
21%
7%
4%
<1%
68%
Cobalt Compounds
0.00009
0.00011
0.8
88%
12%
0%
0%
0%
1,4-Dichlorobenzene
0.13
0.091
1.4
<1%
24%
0%
0%
76%
1,3-Dichloropropene
0.17
0.25
0.7
0%
100%
0%
0%
0%
Diesel Particulate Matter
1.5
0.0033
459
0%
0%
49%
51%
0%
Ethylbenzene
0.56
0.4
1.4
1%
31%
45%
23%
0%
Ethylene Oxide
0.011
0.011
1
7%
24%
0%
0%
69%
Formaldehyde
2.5
0.077
33
<1%
3%
12%
8%
77%*
Methyl Chloride
1.2
0.56
2.2
<1%
1%
0%
0%
99%
Naphthalene
0.19
0.029
6.5
2%
47%
30%
4%
17%
Nickel Compounds
0.0016
0.0021
0.8
40%
36%
3%
5%
16%
PAH/POM
0.015
0.0072**
2
<1%
75%
10%
15%
0%
Perchloroethylene
0.43
0.17
2.6
<1%
44%
0%
0%
56%
1,1,2-Trichloroethane
5.5E-6
0.063
9.0E-5
78%
22%
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.
