History of Visible Emissions Observations in the United States
A timeline of opacity regulation from the 1800s to today
History of opacity observations — timeline
| Year | Milestone |
|---|---|
| 1859 | First successful court case in the U.S. regarding emissions — in New Orleans against a blacksmith, stating that odors and smoke from the business constituted a nuisance. |
| 1881 | First two U.S. cities to adopt smoke control ordinances: Chicago and Cincinnati. |
| 1897 | U.S. begins to use the Ringelmann Scale. Ringelmann had developed his work in the 1870s in France. |
| 1910 | U.S. Bureau of Mines formed. |
| In the early 1900s, many court cases arose citing smoke as a nuisance. | |
| 1910 | Rochester, NY — statute upheld the use of Ringelmann. Restrictions placed on smoke production with limits on how long dense smoke can be produced. |
| 1912 | Of the 28 U.S. cities with populations over 200,000, 23 now had smoke ordinances. |
| 1916 | Northwestern Laundry vs. Des Moines — important case that upheld the right of the city to declare dense smoke in portions of the city a public nuisance. |
| 1948 | After pollution-related deaths and illness in Donora, PA, the U.S. Surgeon General declared smoke and other pollutants a health hazard, resulting in funding for air pollution studies. |
| By the end of the 1940s, smoke and air pollution were recognized as health hazards. | |
| 1950 | California passes California Rule 50A to limit smoke emissions. This rule was used by a majority of U.S. states and was included in the NSPS in 1970. |
| 1953 | First smoke school in Los Angeles County, using the equivalent opacity method. |
| 1953 | Equivalent opacity added to the Ringelmann system by the Los Angeles Air Pollution Control Board, allowing for measuring emissions in colors other than black. |
| 1955 | Federal Air Pollution Act — the first federal pollution control act. |
| 1963 | Initial Clean Air Act passed by U.S. Congress, providing funding to air pollution control agencies. |
| 1967 | Federal Air Quality Act — required states to establish Air Quality Regions and adopt Ambient Air Quality Standards (precursor to State Implementation Plans). |
| 1968 | Joint study by industry and government released by the Federal Air Pollution Control office: AP-30, Optical Properties and Visual Effects of Smoke-Stack Plumes. |
| 1970 | The U.S. Environmental Protection Agency (EPA) formed on December 2. |
| 1970 | Clean Air Act updated — formed the basis of U.S. air pollution policies. |
| 1974 | Method 9 promulgated by the EPA and still in use today. |
| 1977 | Additional amendments to the Clean Air Act. |
| 1982 | Method 22 for fugitive emissions promulgated by the EPA. |
| By the end of the 1980s, Method 9 had effectively corrected excessive opacity/particulate emissions from most facilities. | |
| 1990 | 1990 Clean Air Act amended to include Title V — developed to create a uniform national permitting system, requiring companies that create air pollutants to obtain a permit. |
| In 1997, Title V began to shift focus from enforcement to maintenance of air quality through continued use of Method 9. | |
Sources: EPA Visible Emissions Student Manual » EPA Visible Emissions Field Manual »