Nitrogen oxide
{{#badges: CoalSwarm}} Nitrogen is the most common part of the air we breathe: about 80% of the air is nitrogen. When air is heated, like in coal boilers, nitrogen atoms break apart and join with oxygen, forming nitrogen oxides (NOx) (rhymes with "socks"). NOx can also be formed from the atoms of nitrogen that are trapped inside coal. Coal combustion release oxides of nitrogen, which react with volatile organic compounds in the presence of sunlight to produce ground-level ozone, the primary ingredient in smog.[1][2]
In atmospheric chemistry and air pollution and related fields, nitrogen oxides refers specifically to NOx (NO and NO2).[3]
Contents
Health and environmental effects
In the air, NOx is a pollutant. Coal combustion release oxides of nitrogen, which react with volatile organic compounds in the presence of sunlight to produce ground-level ozone, the primary ingredient in smog. Asthma exacerbations have been linked specifically to exposure to ozone. Nitrogen oxide also contributes to fine particulate matter (PM), found in soot, which is also linked to a host of serious health effects.[4]
Exposures to ozone and PM are both correlated with the development of and mortality from lung cancer. Recent research suggests that nitrogen oxides and PM2.5, along with other pollutants, are associated with hospital admissions for potentially fatal cardiac rhythm disturbances. Cities with high nitrogen dioxide (NO2) concentrations have death rates four times higher than those with low NO2 concentrations, suggesting a potential correlation.[4]
NOx also harms the environment, contributing to acidification of lakes and streams (acid rain).[5]
Aging coal plants "grandfathered" in after passage of the Clean Air Act have been particularly linked to large quantities of harmful emissions.[6][7]
Regulation
The EPA Office of Air Quality Planning and Standards (OAQPS) has set National Ambient Air Quality Standards under the Clean Air Act for six principal pollutants, which are called "criteria" pollutants: sulfur dioxide, particulate matter, nitrogen oxides, ozone, lead, and carbon monoxide. After the EPA sets or revises each standard and a timeline for implementation, the responsibility for meeting the standard falls to the states. Each state must submit an EPA-approved plan that shows how it will meet the standards and deadlines. These state plans are known as State Implementation Plans (SIPs)." [8]
Transport Rule
Acting under federal court order, the Obama administration proposed new air-quality rules on July 6, 2010, for coal-burning power plants. The pollutants being singled out in the new rule making — sulfur dioxide and nitrogen oxides — are easily carried by the wind and affect states and cities far downwind from the plants where they are produced, and react in the atmosphere to form fine particulates and ground-level ozone (smog). The proposed regulation would apply to power plants in 31 states east of the Rockies, with the exception of the Dakotas, Vermont, New Hampshire and Maine. The proposed rules will replace the EPA's 2005 Clean Air Interstate Rule.[9][10]
Gina McCarthy, head of the EPA’s air and radiation office, said the new rules would reduce emissions of sulfur dioxide and nitrogen oxides by hundreds of thousands of tons a year and bring $120 billion in annual health benefits. Those benefits, Ms. McCarthy said, include preventing 14,000 to 36,000 premature deaths, 23,000 nonfatal heart attacks, 21,000 cases of acute bronchitis, 240,000 cases of aggravated asthma and 1.9 million missed school and work days. Additionally, the rule would substantially reduce unhealthy smog. The cost of compliance to utilities and other operators of power plants would be $2.8 billion a year, according to E.P.A. estimates.[9]
The proposed regulation will require utilities operating coal-burning plants to install scrubbers and other technology to reduce emissions of the pollutants. Some companies may decide to retire older plants rather than invest in new control measures because other new rules under the Clean Air Act are expected in the coming years. The new rules do not address power plant emissions of carbon dioxide and five other pollutants that contribute to global warming. The Obama administration is moving forward with a plan to phase in regulation of such heat-trapping gases, a move that is being challenged in Congress and in the courts.[9]
Resources
References
- ↑ "Knocking the NOx Out of Coal" DOE, accessed September 2010.
- ↑ "Coal Power: Air Pollution," Union of Concerned Scientists, accessed September 2010
- ↑ United States Clean Air Act
- ↑ Jump up to: 4.0 4.1 Alan Lockwood, Kristen Welker-Hood, Molly Rauch, Barbara Gottlieb,"Coal's Assault on Human Health" Physicians for Social Responsibility Report, November 2009
- ↑ "The Health Risks of Burning Coal for Energy" The Environmental Defense Fund, September 5, 2006
- ↑ "Deadly Power Plants? Study Fuels Debate" MSNBC.com, June 9, 2004
- ↑ "America's Biggest Polluters: Carbon Dioxide Emissions from Power Plants in 2007" Environment America, November 24, 2009
- ↑ "NAAQS" Sierra Club, accessed July 2010.
- ↑ Jump up to: 9.0 9.1 9.2 John Broder, "New Rules Issued on Coal Air Pollution" New York Times, July 6, 2010.
- ↑ "Proposed Transport Rule Would Reduce Interstate Transport of Ozone and Fine Particle Pollution," EPA Fact Sheet, accessed July 8, 2010
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