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In past years, Maryland’s typically hot, muggy summer days were often accompanied by poor air quality. Days with soaring temperatures, intense sunlight and stagnant air cause pollution from power plants, vehicles, and maintenance activities to “cook” in the atmosphere and form a secondary pollutant – ground level ozone. This summer, Maryland’s air quality was much healthier than past summers that had comparably hot weather like that experienced in 2006.
Power plants and vehicles can emit nitrogen oxides (NOx) and activities using solvents, paints and gasoline can release volatile organic compounds (VOCs) that react to sunlight and high temperatures to form ozone. When there is a high-pressure system in place and there is little or no wind, ground level ozone can form and stay in place for extended periods. These summer weather patterns may also bring air pollution that was formed hundreds of miles away into Maryland.
Even When Things Get Heated.
Maryland experienced some very hot temperatures and weather conditions this summer that were conducive to ground level ozone formation. Regional ground level ozone however, was much lower than in past years with similar weather patterns. In 2006, Maryland observed a total of 20 eight-hour exceedance days. An exceedance is when the daily maximum ozone levels, averaged over an eight-hour period, reached Unhealthy for Sensitive Groups or above on the Air Quality Index (AQI). This number of violations was much lower than the historical average of 31 days during the 10-year period of 1996 to 2005.
“When we have those hot spells, the trend has been to see widespread ozone pollution for the Mid-Atlantic region,” says Tad Aburn, director of the Air and Radiation Management Administration of the Maryland Department of the Environment (MDE). “In recent years, ozone episodes have been less frequent and of shorter duration.”
“Cleaner air was the result of cooler weather in 2003 and 2004,” explains Michael Woodman, a meteorologist with MDE. “However, the general weather pattern this summer provides evidence that regional pollution control programs are effective in reducing ozone pollution.”
Don’t Nox It- It Works!
In 2003, the first phase of NOx pollution reductions at power plants went into effect through a federal program known as the NOx State Implementation Plan. The program required power plants to install pollution control technology. Federal measures require additional NOx controls for cars, while states are controlling the pollution amount from paints and other consumer products. Additionally, Maryland’s Healthy Air Act, signed into law by Governor Robert L. Ehrlich, Jr. on April 6, 2006, will further reduce power plant emissions in Maryland.
“The Healthy Air Act and other regulations are key to bringing Maryland into compliance with new federal air quality standards,” says MDE Secretary Kendl P. Philbrick. “Maryland continues to be a leader in air quality and ensuring that its citizens can breath clean air.”
Click here for more information about the Healthy Air Act.
Click here for more information about Maryland’s Air Quality.
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