1996 Air Toxics Assessment for New Jersey

In order to determine whether the New Jersey air concentrations predicted for the 33 air toxics in USEPA’s1996 National-Scale Air Toxics Assessment (NATA) presented a potential problem for human health, NJDEP compared them to their chemical-specific health benchmarks. To do this, we divided the modeled air concentration by the health benchmark concentration to get a number we call a risk ratio. If the risk ratio for a specific chemical is less than one, the air concentration does not pose a health risk. If it is greater than one, it may be of concern. The risk ratio also shows just how much higher or lower the estimated air concentration is than the health benchmark.

For more information on health benchmarks, risk assessment, and health effects of air toxics, click here.

Our preliminary analysis of the state and county average air toxics concentrations generated by NATA indicates that 19 of the chemicals were predicted to exceed their health benchmarks in one or more counties in 1996. 18 of these are cancer-causing (carcinogenic) chemicals, and one (acrolein) is not carcinogenic. Predicted concentrations of these 19 pollutants vary around the state, depending on the type of sources that emit them. This is summarized in the table below. For more information click on point, area, and mobile sources, and background concentrations.

For more information on which areas are impacted by these chemicals of concern, see the chemical-specific risk maps tab on the left.

1996 Chemicals of Concern in New Jersey

Pollutant of Concern Extent Primary Source of Emissions
Benzene Statewide Mobile; Background Concentration
1,3-Butadiene Statewide Onroad Mobile
Carbon Tetrachloride Statewide Background Concentration
Chloroform Statewide Background Concentration; Point
Diesel Particulate Matter Statewide Nonroad Mobile
Ethylene dibromide Statewide Background Concentration
Ethylene dichloride Statewide Background Concentration
Formaldehyde Statewide Mobile
Acrolein 20 Counties Mobile
Polycyclic organic matter 20 Counties Area
Chromium compounds 17 Counties Area
Acetaldehyde 13 Counties Mobile
Perchloroethylene 11 Counties Area; Background Concentration
7-PAH 5 Counties Area
Arsenic compounds 4 Counties Area; Point
Cadmium compounds 4 Counties Area
Nickel compounds 4 Counties Area
Beryllium compounds 1 County Area
Hydrazine 1 County Area

* For more information on which areas are impacted by the chemicals of concern, see the chemical-specific maps.

To see a state map showing the spatial variation in modeled air concentrations (at the census-tract level) for one of the nineteen chemicals of concern, click on the map:



Carbon Tetrachloride


Diesel Particulate Matter

Ethylene dibromide

Ethylene dichloride



Polycyclic organic matter

Chromium compounds




Arsenic compounds

Cadmium compounds

Nickel compounds

Beryllium compounds



To see a statewide or county -specific table containing the 1996 NATA-based risk results (including ambient air concentrations, health benchmarks, risk ratios, and source category contributions) for each of the 19 air toxics of concern, click on statewide or the county names below.

For Each Table:

  • 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.
  • Acetaldehyde 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.






Cape May

















Previous NATA Risk Results

USEPA has completed six National-Scale Air Toxics Assessments, every third year beginning with the 1996 NATA. Before that, they conducted a “Cumulative Exposure Project” (CEP) for 1990 which also included an assessment of air toxics. However, they emphasize that the methods used to conduct emissions inventories, modeling, and risk assessment vary somewhat from year to year, so the results are not exactly comparable.

New Jersey’s interpretation of past USEPA data is available below.

1990 CEP Results for NJ