Vegetation Damage from Air Pollution

Abstract

Air must be considered as an important natural resource vital to animals and plants for their life processes and to industry and transportation for combustion purposes. The quality of the air, or the chemical composition of its minor constituents, varies as a result of emission of contaminants from all of man’s activities including the generation of energy, manufacturing of goods, and disposal of various types of wastes. The amounts of the major constituents of air--nitrogen and oxygen--are fairly constant and together account for ninety-nine per cent of the atmosphere near the earth’s surface. In clean air the remaining one per cent is made up of carbon dioxide, water vapor and a variety of other compounds. The minor gaseous constitutents of the air, however, often vary as a result of emissions from the various activities noted above. Thus the quality of the air, when altered by many of these contaminants, may have profound effects on the growth and development of vegetation because gases enter the leaves during the course of normal gas exchange and, if toxic, kill cells and tissues and otherwise interfere with the plant’s normal growth processes.