Coal pollution mitigation emissions of sulfur dioxide or oxides of nitrogen associated with the utilization of coal in the generation of electricity." Before being adopted in this fashion, historically "clean coal" was used to refer to clean-burning coal with low levels of impurities, though this term faded after rates of domestic coal usage dropped. The term appeared in a speech to mine workers in 1918, in context indicating coal that was "free of dirt and impurities." In the early 20th century, prior to World War II, clean coal (also called "smokeless coal") generally referred to anthracite and high-grade bituminous coal, used for cooking
Environmental impact of the coal industry atmospheric CO peaks at 563 parts per million (ppm) in the year 2100. Under the four coal phase-out scenarios, atmospheric CO peaks at 422–446 ppm between 2045 and 2060 and declines thereafter. Coal also contains low levels of uranium, thorium, and other naturally occurring radioactive isotopes which, if released into the environment, may lead to radioactive contamination. Coal plants emit radiation in the form of radioactive fly ash, which is inhaled and ingested by neighbours, and incorporated into crops. A 1978 paper from Oak Ridge National Laboratory estimated that coal-fired power plants of that time may contribute a whole-body committed