Troposphere: Trace Gas Photochemistry and the Impact of Pollution

Over the past decade great strides have been made in our understanding of the trace gas composition of the troposphere and the physical, chemical, and biological processes that control this composition. It is now recognized that the production of free radical species in the presence of solar radiation leads to a complicated series of reactions. These reactions tend to oxidize reduced species released at the earth's surface, transforming them into soluble forms which can be removed in rain and other precipitation. Thus, tropospheric photochemistry represents the atmospheric link in the biogeochemical cycling of the elements and in so doing may influence important environmental parameters such as surface temperature, the acidity of rainfall, the column abundance of stratospheric ozone, and the concentration of potentially toxic gases.