### Question
What is the definition of air pollutant?


### Answer
The definition of **air pollutant** is as follows in *42 U.S.C. § 7602*:

> any air pollution agent or combination of such agents, including any physical, chemical, biological, radioactive (including source material, special nuclear material, and byproduct material) substance or matter which is emitted into or otherwise enters the ambient air

#### Citation:
  - *42 U.S.C. § 7602*
  - Heading: **CHAPTER 85-AIR POLLUTION PREVENTION AND CONTROL > SUBCHAPTER III-GENERAL PROVISIONS**

