Also known as toxic air pollutants or hazardous air pollutants, these are chemicals that cause or may cause serious effects in humans, and may be emitted into the air in quantities that are large enou [..]

Small sources of air pollution which by themselves may not emit very much, but when their emissions are added together they may account for a sizable portion of the total emissions of air toxics. In N [..]

The pollutant levels that are found throughout the continental United States even in "clean air locations," areas where no man-made air toxic emissions would be expected. They are a [..]

A chemical that has been shown to cause cancer, either in people or animals.

USEPA's Cumulative Exposure Project for 1990.

long duration or frequent recurrence.

A list of activity categories that emit pollutants and an estimate of how much is emitted by each.

Contact with a substance through inhalation, ingestion or some other means for a specific period of time.

Hazardous air pollutant. In general, an "air toxic." Specifically, this also refers to one of the 188 specific pollutants

The chemical-specific air concentration below which there should be no significant harm to human health. For a carcinogen (cancer-causing chemical), the health benchmark is set at the air concentratio [..]