Acid Rain and Other Airborne Pollutants

SINCE THE INDUSTRIAL REVOLUTION GATHERED MOMENTUM in the middle of the nineteenth century, human activities have added more and more substances to those that circulate naturally among the air, water, soil, and all living things (Smith, 1872). Almost everything human beings do on a large scale influences the chemistry of the atmosphere. Some of the airborne substances introduced by human activity are beneficial for life in general and human life in particular. They provide oxygen and other nutrients that are essential for humans and for the growth of crops and forests. Other substances are inert biologically. Still others are detrimental because they cause stress in plants, animals, and microorganisms. They also alter surface and ground water quality, aggravate nutrient deficiencies in soils, or accelerate the soiling, weathering, or corrosion of engineering and cultural materials. In recent decades, the term acid rain has captured the imagination of the public in much the same way and for substantially the same reasons that Rachel Carson's Silent Spring (1962) captured our imagination in the early 1960s. But acid rain must be recognized as only one special feature of a series of processes. These include emission, transport, transformation, deposition, uptake, and exchange of natural and manmade chemicals between the atmosphere and terrestrial and aquatic ecosystems (Altshuller and Linthurst, 1983). During the past few years, a series of major shifts has been taking place in both scientific and public debates about acid rain, air pollution, and global climate (Comptroller General, 1984; OTA, 1981). These issues are related because all three are manifestations of change in the chemical climate of the Earth, involve many of the same chemical emissions from

Acid rain · Biology · Environmental protection · Pollutant · Atmospheric chemistry and aerosols · Ecology · Environmental Science