Soot is a significant contributor to air pollution. The main sources of soot is coal-fired plants and diesel engines. Soot has also been found to be a major greenhouse gas emission, estimated to be responsible for upwards of sixteen percent of global warming according to a Stanford University study.
In the United States, the Environmental Protection Agency’s annual standard on soot is fifteen micrograms per cubic meter of air. This standard has not been altered since 1997 despite environmental groups and states insisting otherwise. Eleven states have sued the EPA due to their lack of revision on the Clean Air Act’s soot regulations, including California and New York. Due to this case, the EPA has recently released proposed changes to the 1997 regulations.
According to the proposal, the EPA would change the soot limit to between twelve and thirteen micrograms per cubic meter. The EPA has indicated that the country has already made significant strides in reducing soot pollution. Despite concerns surrounding the new proposal, the EPA indicates that nearly the entire country would be in compliance with the new proposal by the year 2020 by simply adhering to regulations as they currently stand. However, six counties across the U.S. would not and would need further measures to meet EPA regulations.
The World Health Organization recently announced that they were moving diesel fumes from the level of probable carcinogen to the level of carcinogen. Diesel fumes are considered by the organization to be similar in nature to secondhand smoke and detrimental to health. Other organizations have spoken out against soot pollution as well, including the American Lung Association and numerous environmental groups.
The proposal has not been well received by those in the U.S. government, with many indicating fears of interference with the economy. The EPA has countered such concerns with the aforementioned data indicating all but six counties would be able to easily comply with the standards by 2020 without any true alteration or impact on the economy. A decision on the proposal is expected by December 2012.