A foreign substance that makes somethingdirty, orimpure, especiallywaste fromhuman activities.
1987 January 20, “Airborne Pollutants”, inThe New York Times[1],→ISSN:
Acid rain forms when water in the atmosphere condenses on particles containing acid-formingpollutants, such as sulfate produced by the burning of fossil fuels and nitrogen oxides from automobile exhausts.
