Synopsis Many people spend a substantial part of each day indoors-in many cases, 80 to 90 percent-in a house, an automobile, a waiting room, an office or other workplace, or a confined space accessible to the general public, such as a store or a restaurant. It has been shown that indoor exposure to environmental pollutants cab be substantial. Although there is little epidemiologic evidence on the health effects of indoor pollutants, indoor concentration of some pollutants that already have primary ambient air quality standards exceed those standards. Indoor exposure has been largely overlooked in research on the health effects of environmental pollutants, but it can constitute an important fraction of the total exposure to many pollutants. The sources and characterization of indoor pollution, have been taken a random which cover its decay products, formal dehydrates and other organic substances, asbestos and fibrous glass, combustion products, tobacco smoke, consumer products, odours, temperature and humidity, and other pollutants, not specifically treated. The objective of this book is not a global treatment of every possible hazard encountered indoors, but rather a selective treatment. The chief criterion for selective treatment. The chief criterion for selective is direct or circumstantial evidence that a contaminant causes or is reasonably likely to cause human stress, illness, or material damage indoors.