Deutsch: Luftverschmutzung / Español: Contaminación del aire / Português: Poluição do ar / Français: Pollution de l'air / Italiano: Inquinamento dell'aria /

Air Pollution is the presence of contaminants or Pollutant substances in the air that interfere with human health or welfare, or produce other harmful Environmental effects.

Other definition:
Air pollution is toxic or radioactive gases or particulate matter introduced into the atmosphere, usually as a result of human activity.

Other definition:
Air pollution is one or more chemicals or substances in high enough concentrations in the air to harm humans, other animals, vegetation, or materials. Such chemicals or physical conditions (such as excess heat or noise) are called air pollutants.