EFFECTS OF AIR POLLUTION

People are concerned about air pollution because it affects health and damages property. The potential damage to human beings is of primary concern. Some pollutants are more dangerous to humans than others. This study deals with four of the most dangerous and damaging; particulates, sulfur dioxide, carbon monoxide, and hydrocarbons. It excludes nitrogen oxides because NO_x sources are similar to HC. Of the four, particulates and SO₂ probably affect health the most, although CO and HC are also significant. Discussing sulfur oxides and particulates, Dr. Ian Higgins of the University of Michigan School of Public Health, and Dr. Benjamin Ferris, Jr. of the Harvard School of Public Health say:

There is good evidence that exceptional episodes of pollution cause morbidity and mortality. There is also a good deal of evidence that sustained lower levels of pollution affect health adversely. While the major effects of pollution are on those who are already suffering from disease, particularly of the lungs or heart, evidence, especially studies of children, suggests that pollution can initiate disease as well as merely exacerbate it. Particulate and SO₂ pollution probably plays a considerable role in the development and progression of bronchitis and emphysema. On balance, the evidence suggests that it contributes to the toll of lung cancer.

Higgins and Ferris cite extremely serious diseases whose ill effects have been recorded at fairly low particulate levels. Particulate and SO₂ pollution are expressed in micrograms per cubic meter of air (μg/m³). Since the effects of the two pollutants are stronger when combined than when separate, the U.S. government has set air quality standards accordingly. These standards have been substantially exceeded in Washington, D.C.