Atmospheric pollution.

Air pollution has been directly responsible for increases in mortality and morbidity in the general population during periods known as episodes, when pollutant levels were elevated well above those that occur on a regular basis. The major concern today regarding pollution and health is, however, more subtle--namely, whether the lower levels of pollution to which we are exposed daily are harmful to health. It is extremely difficult to relate specific health problems to specific pollutants, because other environmental and lifestyle factors may contribute to decrements in health. Furthermore, people are generally exposed to mixtures of pollutants, making it difficult to extract the effects caused by individual components, or to determine which combinations are the most hazardous. Community air pollution results from various sources: mobile sources, such as vehicles; stationary sources, such as power plants and factories; and indoor sources, such as building material. Complicating the picture is the fact that many chemicals released into the air may react, producing additional secondary pollutants. This article provides an overview of the major air pollutants that may be of concern in terms of public health.