Atmosphere

The atmosphere is the receiver of many by-products of our society, such us products of combustion of fossil fuels and industrial manufacturing. The studies on chemical pathways of trace atmospheric species are often complexes since the life cycles of such species are linked to an elaborate system of chemical and physical processes. As a result, it is possible that a perturbation in the concentration of one species leads to significant changes in quantity and lifetimes of other trace species; the feedback could also amplify or damp the original perturbation. Trace species can exhibit an enormous range of spatial and temporal variability, depending on their lifetime in the atmosphere. Relatively long-lived species are usually uniformly distributed: in this case strategically located sampling sites around the globe could be adequate to characterize their spatial distribution and temporal trend. As species lifetimes become shorter, their spatial and temporal distributions become more variable.