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List of State Officials - Martin O'Malley, Governor; Anthony Brown, Lt. Governor; Shari T. Wilson, MDE Secretary 

Volume IV, Number 1

 October 2009

eMDE is a quarterly publication of the Maryland Department of the Environment. It covers articles on current environmental issues and events in the state. 

Air Pollution 101, Part 2 – Maryland’s Air Quality Improves

By Angelo Bianca, Air and Radiation Management Administration

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Think back to movies filmed in the large cities of the 1970s with one feature in common – shots of a visibly polluted skyline.

Back then, large manufacturing operations with dark smoke billowing from tall smokestacks signified industrial strength and economic progress. Detroit, Pittsburgh, Cleveland, Chicago, and, yes, Baltimore were prime examples of cities with thriving industries — and thriving pollution.

But Maryland’s air quality has improved tremendously in the past 30 years.

While there were some air quality improvements in the early years of the Clean Air Act, the Clean Air Act Amendments of 1990 set the stage for real change. Congress mandated that the Environmental Protection Agency set national ambient air quality standards protective of public health and that states measure air quality and develop plans to address areas that fail to meet the established standards.

Maryland’s most pervasive air pollution problem in 1990 was ground-level ozone. An ozone problem still exists but much progress has been made in reducing its severity. In 1990, much of Maryland was considered to have a severe ozone problem as measured against a one-hour ozone standard of 125 parts per billion. The chart on the left shows the improvement against that standard, to a point where the State achieved the one-hour standard in 2005 in the Washington, D.C., metropolitan area and in 2008 in the Baltimore metropolitan area. This achievement was made possible through the implementation of more than 100 pollution control programs that focused on reducing volatile organic compounds and oxides of nitrogen from vehicles, both on and off-road, smokestack sources such as power plants, industries, and incinerators and “area” sources including gas stations, school boilers, paints, solvents, and inks.

The Vehicle Emission Inspection Program (“VEIP”) and federal programs to require cleaner fuels and engines are hallmarks of the pollution reduction programs aimed at the mobile sources sector. To address pollution from smokestacks, numerous industrial sources, such as power plants, incinerators, steel and aluminum mills, cement plants, aircraft manufacturing plants and paper mills, were required to install low-emitting pollution reduction technology. Vapor recovery nozzles at gas stations, spill-proof gas cans, low VOC paints, solvents, adhesives, and consumer products and controls on commercial printers are examples of programs designed to address air pollutants emitted by area sources. 

The one-hour ozone standard was strengthened by the EPA in 2005 by replacing it with a more stringent eight-hour standard set at 85 parts per billion. This was recently lowered to 75 parts per billion. Maryland is making progress toward meeting the more stringent ozone standard. Other indicators demonstrating improved air quality include fewer monitors that exceed the standard on days when the standard is exceeded and a generally lower peak ozone value even on an exceedance day when compared with exceedance days in prior years.

This improvement in air is the result of a continuing effort to reduce pollution from more and more sources and to further reduce pollution from some major source sectors, such as power plants, both locally and nationally. Together, the federal Clean Air Interstate Rule that imposed a limit on power plant emissions via a cap-and-trade policy, along with the Maryland Healthy Air Act, which imposed stringent emission standards on coal-fired power plants, are leading to significant improvements in air quality. Power plant emission control technology installed as a result of the federal rule has helped reduce emissions that can be transported to Maryland via prevailing winds. (This rule is currently being restructured due to legal action.) Tightening emission standards on fuels and engines and requiring many commercial products to further lower pollutant content has also aided the effort.

The EPA set new air quality standards in 2006 for the pollutant fine particulate matter. Based on 2008 data, Maryland has achieved compliance with both the annual and the daily fine particulate matter standards. This is due, in large part, to pollution reduction programs focused on diesel engines, power plants, and fuels. The EPA is expected to make this standard more stringent, so additional pollution reduction efforts will be undertaken in the future.

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Editorial Board
Maryland Department of the Environment
1800 Washington Boulevard, Baltimore, MD 21230
http://mde.maryland.gov/
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