The Atmospheric Aerosol

摘要: The term aerosol refers to a suspension of fine particles in air. principal sources the troposphere are: (a) surface agitation by wind force, which generates soil dust, sea salt particles, and biogenic material; (b) high temperature processes including volcanic eruptions, forest fires anthropogenic combustion processes; (c) chemical reactions leading compounds with low vapor pressures such as oxidation SO2 sulfuric acid, NO2 nitric or glyoxal oxalic neutralization acids ammonia alkaline minerals form water-soluble salts. Particles size range above ∼0.1 μm act cloud condensation nuclei (CCN). While most clouds evaporate again so that are recycled, precipitation transfers material earth surface. incorporated rain water during formation precipitating (nucleation scavenging) attachment drops (below-cloud scavenging). Dry deposition also contributes removal from atmospheric boundary layer (primarily >5 μm). Directly emitted usually retain their original character vicinity sources, but transport all undergo modification both coagulation small accumulation resulting occurring gas phase clouds. In stratosphere source is conversion sulfur acid.