This presentation discusses the properties and effects of aerosols in the atmosphere. Aerosols are tiny solid or liquid particles suspended in air that come from both natural sources like dust, sea spray and volcanic eruptions, as well as human sources such as combustion of fossil fuels and biomass burning. Aerosols can impact climate in various ways by scattering and absorbing solar radiation, acting as cloud condensation nuclei, and altering precipitation patterns which collectively are known as aerosol indirect effects.