SALEM 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
1.6
0.45
3.6
<1%
2%
2%
1%
95%*
Acrolein
0.035
0.020
1.7
<1%
26%
9%
5%
60%*
Arsenic Compounds
0.00019
0.00023
0.8
10%
14%
5%
3%
68%
Benzene
0.59
0.13
4.6
1%
13%
20%
7%
59%
1,3-Butadiene
0.45
0.033
1.4
<1%
<1%
32%
11%
57%
Cadmium Compounds
0.000077
0.00024
0.3
9%
27%
0%
1%
63%
Carbon Tetrachloride
0.61
0.067
9.1
0%
<1%
0%
0%
100%
Chloroform
0.076
0.043
1.8
<1%
22%
0%
0%
78%
Chromium (hexavalent form)
0.00015
0.000083
1.8
86%
3%
2%
<1%
9%
Cobalt Compounds
0.000028
0.00011
0.2
100%
0%
0%
0%
0%
1,4-Dichlorobenzene
0.042
0.091
0.5
<1%
50%
0%
0%
50%
1,3-Dichloropropene
0.026
0.25
0.1
0%
100%
0%
0%
0%
Diesel Particulate Matter
0.36
0.0033
110
0%
0%
66%
34%
0%
Ethylbenzene
0.080
0.4
0.2
3%
16%
55%
26%
0%
Ethylene Oxide
0.0094
0.011
0.8
24%
4%
0%
0%
72%
Formaldehyde
1.8
0.077
23
<1%
2%
4%
2%
92%*
Methyl Chloride
1.2
0.56
2.2
1%
<1%
0%
0%
99%
Naphthalene
0.049
0.029
1.7
1%
31%
21%
3%
44%
Nickel Compounds
0.00065
0.0021
0.3
51%
34%
1%
7%
7%
PAH/POM
0.017
0.0072**
2.1
1%
95%
2%
2%
0%
Perchloroethylene
0.08
0.17
0.5
1%
56%
0%
0%
43%
1,1,2-Trichloroethane
0.21
0.063
3.3
0%
100%
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.
