GLOUCESTER 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
1.7
0.45
3.9
<1%
3%
2%
1%
94%*
Acrolein
0.041
0.020
2.1
<1%
18%
9%
9%
64%*
Arsenic Compounds
0.00042
0.00023
1.8
4%
7%
3%
2%
84%
Benzene
0.86
0.13
6.6
1%
10%
17%
9%
63%
1,3-Butadiene
0.066
0.033
2
<1%
<1%
26%
14%
60%
Cadmium Compounds
0.000081
0.00024
0.3
12%
27%
0%
1%
60%
Carbon Tetrachloride
0.61
0.067
9.1
0%
<1%
0%
0%
100%
Chloroform
0.089
0.043
2.1
1%
32%
0%
0%
67%
Chromium (hexavalent form)
0.00015
0.000083
1.8
28%
3%
3%
1%
65%
Cobalt Compounds
0.00018
0.00011
1.7
100%
0%
0%
0%
0%
1,4-Dichlorobenzene
0.073
0.091
0.8
<1%
37%
0%
0%
63%
1,3-Dichloropropene
0.047
0.25
0.2
0%
100%
0%
0%
0%
Diesel Particulate Matter
0.54
0.0033
163
0%
0%
54%
46%
0%
Ethylbenzene
0.11
0.4
0.3
3%
14%
51%
32%
0%
Ethylene Oxide
0.0094
0.011
0.8
15%
11%
0%
0%
74%
Formaldehyde
2.0
0.077
26
<1%
2%
4%
3%
91%*
Methyl Chloride
1.2
0.56
2.2
<1%
<1%
0%
0%
100%
Naphthalene
0.062
0.029
2.1
2%
34%
20%
6%
38%
Nickel Compounds
0.00075
0.0021
0.4
64%
13%
2%
8%
13%
PAH/POM
0.011
0.0072**
1.6
2%
84%
5%
9%
0%
Perchloroethylene
0.13
0.17
0.7
<1%
48%
0%
0%
52%
1,1,2-Trichloroethane
0.06
0.063
0.9
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.
