OFFICIAL SITE OF THE STATE OF NEW JERSEY

The NJDEP Air Quality Permitting Program uses risk assessment to evaluate potential effects on public health from facilities seeking permits to emit air toxics. An overview of the risk assessment process can be found in Technical Manual 1003, which also includes details on preparing a risk assessment. However, many permit applications can be evaluated using a risk screening worksheet. Information on risk assessment for various types of emissions can be found below.

Health Effects of Air Toxics

Air toxics can be broadly grouped into two categories according to their health effects: carcinogens (cancer-causing) or noncarcinogens. Carcinogens are those chemicals that have been shown to cause cancer, either in people or animals. Noncarcinogens have other kinds of health effects, affecting such things as development, reproduction, respiration, the liver, kidney or other organs. Health effects of chemicals are discovered in a number of ways. Researchers can study groups of people that have been exposed to the chemicals in the past, usually at the workplace. They can also expose volunteers to specific amounts of a chemical and record the effects. Most health effects information comes from studies of animals that are exposed in the laboratory to specific doses of a chemical for specific periods of time.

Using Health Benchmarks

Unit risk factors are measures used for carcinogens that estimate the increased risk of getting cancer associated with the concentration of the chemical in the air that you are breathing. A risk of less than one in a million is considered to be negligible.

Reference concentrations are measures developed for noncarcinogens. Exposure to a chemical below the reference concentration, even over a long period of time, is not expected to have any negative effect on health.

These unit risk factors and reference concentrations can be used as health benchmarks, to evaluate the potential health effects of air toxic concentrations. For carcinogens, the health benchmark is the air concentration that would result in a one in a million increase in the risk of getting cancer if a person inhaled that concentration over a whole lifetime. For noncarcinogens, health benchmarks are set at the reference concentration. Air concentrations that are below these health benchmarks are not expected to be harmful to human health. It is not always clear, however, how far above the health benchmark an air concentration has to be before it becomes harmful. Types of harmful health effects and actual harmful levels will vary substantially from pollutant to pollutant.