Air pollution is the introduction of particulates, biological molecules, or other harmful materials into Earth's atmosphere, causing diseases, allergies, death to humans, damage to other living organisms such as animals and food crops, or the natural or built environment.
While the load of chemical species in atmosphere has exceeded the limits of its capability, there will be environmental issue causing disease and environmental damage. The source of air pollutants(SO2, NOx, VOC, etc) conclude both nature(volcano, desert, wild fire, etc) and anthropogenic(industry, domestic, vehicle, etc). Emission, transport and chemical reaction are three fundamental process related to air pollution.
