Another timely title on an important environmental issue from the author of Acid Rain (1983) and The Greenhouse Effect (1986). In this ""Impact Book,"" Gay considers the dual problems of pollution or smog in the troposphere and the depletion of the ozone layer, or ""hole,"" in the stratosphere: both are related to air pollution. She describes efforts to reduce ozone produced by auto emissions and industry, ""Clear Air Legislation,"" and current research. Implications of ozone loss in the stratosphere include health risks (cancer due to increased radiation) and environmental effects (the warming trend resulting from the greenhouse effect; a decrease in photosynthesis and crop production; endangered aquatic life). An outstanding introduction to a complex problem, enhanced by lucid writing and sources current to October 1988. List of organizations; extensive bibliography; index and photos (not seen).