Union County Average 1999 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
5
2%
5%
59%
13%
21%
Acrolein
0.2
0.020
12
0.09%
23%
48%
29%
0%
Arsenic Compounds
0.0001
0.00023
0.4
6%
94%
0%
0%
0%
Benzene
2
0.13
16
0.5%
10%
53%
14%
22%
Bis(2-ethylhexyl)phthalate
2
0.42
4
0.2%
0.05%
0%
0%
100%
1,3-Butadiene
0.2
0.033
6
0.05%
4%
41%
20%
35%
Cadmium Compounds
0.00008
0.00024
0.3
14%
85%
0%
0.9%
0%
Carbon Tetrachloride
0.3
0.067
4
0.01%
0.5%
0%
0%
99%
Chloroform
0.1
0.043
3
0.3%
67%
0%
0%
33%
Chromium (hexavalent form)
0.0001
0.000083
1.5
21%
64%
14%
0.5%
0%
1,4-Dichlorobenzene
0.09
0.091
1
4%
96%
0%
0%
0%
1,3-Dichloropropene
0.2
0.25
0.7
0%
100%
0%
0%
0%
Diesel Particulate Matter
2
0.0033
664
0%
0%
39%
61%
*
Ethylene Dibromide
0.03
0.0017
19
0.07%
0.02%
0%
0%
100%
Ethylene Dichloride
0.05
0.038
1.2
1%
0.3%
0%
0%
99%
Ethylene Oxide
0.007
0.011
0.6
16%
84%
0%
0%
0%
Formaldehyde
3
0.077
34
2%
4%
39%
22%
34%
Methyl Chloride
1
0.56
2
0.04%
1%
0%
0%
99%
Naphthalene
0.1
0.029
5
2%
69%
19%
10%
0%
Nickel Compounds
0.002
0.0064
0.3
3%
93%
3%
0.5%
0%
Perchloroethylene
0.3
0.17
1.9
0.6%
58%
0%
0%
41%
1,1,2,2-Tetrachloroethane
0.07
0.017
4
0.2%
0.7%
0%
0%
99%
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.
