Air Quality Engineers

The growth of cities and factories during the Industrial Revolution was a major contributor to the decline of air quality. Some contaminates (pollutants) have always been with us, for instance, particulate matter (tiny solid particles) from very large fires, volcanic eruption, or dust caused by wind. However, human populations were not really concentrated enough, nor did the technology exist, to produce conditions that are today considered hazardous until about 200 years ago. The industrialization of England in the 1750s, followed by that of France in the 1830s and Germany in the 1850s, created high-density populations of millions of people who were drawn to cities to work in the smoke-belching factories, leading to huge increases in airborne pollutants. Work conditions in the factories were notoriously bad, and with no pollution-control or safety measures, living conditions in cities rapidly became equally bad. The severely polluted air was a major cause of respiratory and other diseases.

America's cities were slightly smaller and slower to industrialize; they were also more spread out than European capitals like London. Even so, levels of sulfur dioxide were so high in Pittsburgh in the early 1900s that ladies' stockings would disintegrate upon prolonged exposure to the air. The rapid growth of the American automobile industry in the first half of the 20th century contributed greatly to air pollution in two ways: initially, from the steel factories and production plants that made economic giants out of places like Pittsburgh and Detroit, and then from the cars themselves. This became an even greater problem as cars enabled people to move out from the fetid industrial city and commute to work from the suburbs. Mobility independent of public transportation greatly increased auto exhaust and created such modern nightmares as rush-hour traffic.

The effects of air pollution were and are numerous. Particulate matter reacts chemically with heat to form ground-level ozone, or smog. Sulfur and nitrogen oxides form acid rain, which can cause extensive property damage over long periods. Carbon monoxide, the main automobile pollutant, is deadly at a relatively low level of exposure.

Air pollution affects the environment not only in well-publicized phenomena like acid rain and destroying the ozone layer, but in less obvious ways as well. For example, increased asthma rates in cities has often been statistically tied to the amount of pollution in the environment. Because pollution is so difficult to remove from the air, and because its effects are so difficult to alter, the problem tends to be cumulative and an increasingly critical public health issue.

Some private air pollution control was implemented in the 20th century, mainly to prevent factories from ruining their own works with corrosive and unhealthy emissions. The first attempt at governmental regulation was the Clean Air Act in 1955, but because environmental concerns were not considered viable economic or political issues, this act was not very effective.

As environmentalists became increasingly visible and vigorous campaigners, the Air Quality Act was established in 1967. The Environmental Protection Agency (EPA) created National Ambient Air Quality Standards (NAAQS) in 1971, which set limits on ozone, carbon monoxide, sulfur dioxide, lead, nitrogen dioxide, and particulate levels in the emissions of certain industries and processes. States were supposed to design and implement plans to meet the NAAQS, but so few complied that Congress was forced to extend deadlines three times. Even now, many goals set by the first generation of air-quality regulations remain unmet, and new pollution issues demand attention. Airborne toxins, indoor air pollution, acid rain, carbon dioxide buildup (the greenhouse effect), and depletion of the ozone layer are now subjects of international controversy and concern.