Atmospheric aerosols are very fine particles suspended in air. They are formed by the dispersal of material at the earth's surface (primary aerosols), or by reaction of gases in the atmosphere (secondary aerosols).
They include sulphates and nitrates from the oxidation, respectively of sulphur dioxide and nitric oxide, during the burning of fossil fuels; organic materials from the oxidation of VOCs (Volatile Organic Compounds); soot from fires; and mineral dust from wind-blown processes.
Aerosols affect the climate by
- Increasing scattering of sunrays
- Interacting with atmospheric gases
- Contributing to greenhouse effect
- Interacting with clouds and changing the rainfall pattern
- Forming smog with water vapour