Union 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
3
0.45
6
0.05%
5%
41%
8%
46%
Acrolein
0.1
0.020
6
0.4%
13%
67%
20%
0%
Arsenic Compounds
0.0007
0.00023
3
2%
13%
7%
6%
72%
Benzene
2
0.13
18
1%
12%
38%
11%
38%
1,3-Butadiene
0.2
0.033
5
1%
0.05%
40%
15%
44%
Cadmium Compounds
0.0001
0.00024
0.5
7%
50%
0%
2%
41%
Carbon Tetrachloride
0.6
0.067
9
0.001%
0.2%
0%
0%
99.8%
Chloroform
0.2
0.043
4
1%
50%
0%
0%
49%
Chromium (hexavalent form)
0.0004
0.000083
5
7%
9%
4%
1%
79%
1,4-Dichlorobenzene
0.1
0.091
1.4
0.3%
65%
0%
0%
35%
1,3-Dichloropropene
0.2
0.25
0.7
0.00005%
100%
0%
0%
0%
Diesel Particulate Matter
2
0.0033
506
0%
0%
28%
72%
*
Ethylbenzene
0.7
0.4
1.7
2%
26%
52%
20%
0%
Ethylene Oxide
0.01
0.011
1.1
12%
22%
0%
0%
66%
Formaldehyde
3
0.077
36
1%
3%
25%
11%
60%
Methyl Chloride
1
0.56
2
0.4%
0.7%
0%
0%
98.9%
Methyl tert-butyl ether
3
3.8
0.7
1%
13%
41%
45%
0%
Naphthalene
0.1
0.029
5
3%
60%
12%
3%
22%
PAH/POM
0.02
0.0075
2
3%
74%
14%
9%
0%
Perchloroethylene
0.4
0.17
3
0.5%
44%
0%
0%
56%
1,1,2-Trichloroethane
2.6E-6
0.063
4.0E-5
53%
47%
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.
