ABSTRACT
Aerosols are de™ned as small solid or liquid particles suspended in the atmosphere for a period of a few hours to a few days, depending on their size. They have a complex chemical composition that mainly depends on their source, which may be natural and/or anthropogenic. Natural aerosols may originate from forest ™res, sea spray, dust storms, and volcanoes, whereas anthropogenic aerosols are emitted due to human activities, such as biomass burning, industry, and transportation (i.e., car, truck, ship, and airplane exhaust). The coupling between the two sources can further complicate the composition, and thus the processing, of aerosols in the atmosphere.
