Air Pollution

Urban life in America has included several factors that have compromised the quality of the air residents breathe. Among these factors are industrial processes, transportation, heat, and the reliance upon fossil fuels to provide the energy for commercial and residential activity. This dynamic was in place in the colonial period; Thomas Jefferson lamented the development of industry in America, concerned that it would bring the smoke and corruption of European urbanization (where complaints of smoke produced by coal date back to the 1400s) to the pristine landscape. By the time Jefferson had ascended to the presidency, this transition had already begun in the colonies, with smoke and odors from New England lumber mills befouling local air.

Jefferson's concerns anticipated the toll of industry, and as American cities developed large steel, textile, and transportation industries over the 19th century, the use of coal to fuel production belched large and constant clouds of smoke and sulphur dioxide over urban skies. Smoke and ash became particularly acute problems in the second half of the 19th century. Factors contributing to urban smoke included industrial smokestacks, the incineration of municipal waste, widespread use of railroads for commerce and transit, and domestic heating and cooking. Most of these activities involved the burning of coal as the primary source of fuel, and soft grades of coal produced highly visible plumes of black smoke and fly ash. The concentration of smoke in Northern cities grew especially severe during winter months when thousands of stoves burned coal to warm homes; on some days, cities such as Pittsburgh and Saint Louis would have black skies at noon.

Public health advocates worried about the effects of smoke on children, the infirm, and workers. By the end of the 19th century, women's associations such as civic associations and smoke abatement leagues emerged to critique the problem of smoke. Between 1890 and 1940, these associations teamed with civic engineers to compel several cities using soft coal for heating and industry to pass smoke control regulations. Several measures passed with limited success. Municipalities began using the Ringelmann Chart to measure coal smoke in the early 1900s. The technique, developed by Maximillian Ringelmann of France in the late 1800s, measured the darkness of smoke with four different black grids on a white background, which was placed a distance away from smokestacks for a set time. Smoke control efforts in Chicago and other cities quickly adopted the technique, defining air pollution as visible smoke in need of control. Engineering developments joined with public pressure to keep smoke control a priority in local politics. The Smoke Abatement League of Saint Louis erected billboards in 1939 claiming smoke cost each resident of the city $19 per year because of cleaning and health costs.

Coal-washing municipal ordinances (pioneered in Saint Louis in 1940 and adopted by dozens of cities by the end of 1941) and a gradual transition in urban domestic heating fuel supplies away from coal in favor of natural and manufactured gas and oil mitigated the smoke problem between 1940 and 1950, though industrial uses, power plants, and railroads continued to put visible smoke into urban skies. The days of black skies at noon were over.

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