The chemistry of the atmosphere and its perturbations through human activities

The chemistry of the atmosphere results from a complex series of reactions that involve many atmospheric trace gases and that are initiated through sunlight absorption by ozone, formaldehyde and other trace gases. Within the troposphere, this chemistry forms ozone and many highly reactive intermediates and molecules including acids, peroxides, and other undesirable products. However, in contrast, stratospheric chemistry leads to the destruction of natural stratospheric ozone, our protective shield from short ultraviolet radiation at the earth's surface. This results when halocarbons, relatively innocuous, unreactive compounds in the troposphere, are released at the surface of the earth and are ultimately transported to the stratosphere. Here sunlight dissociates them into highly reactive molecular fragments that start a chain of chemical events which destroy stratospheric ozone. Atmospheric scientists, industrial and academic scientists and engineers of other disciplines, as well as the general public, are becoming more aware of the importance of understanding the changes which are occurring in the atmosphere as a result of human activities. We are all interested in minimizing the occurrence of surprises such as the 'ozone hole,' forest damage, etc. The leaders of our countries require advice in designing scientifically sound yet economically realistic solutions to the many problems which result from the anthropogenic perturbations that we induce on our natural system. Clearly the knowledge of atmospheric chemistry as derived from both fundamental and applied chemical studies by scientists from many disciplines will form the basis for sound scientific solutions to these problems.