by Jessica Daniels | Is the District’s air safe to breathe? For the residents in the Washington metro area who suffer from heart and respiratory ailments, not always. The lungs act as filters. When dirty air is inhaled, and there are impurities than cannot be expelled by normal bodily processes, damage can occur, especially for sensitive populations such as children and the elderly. On bad air days, there are increases in hospitalizations and emergency room visits. Symptoms of exposure to bad air range from coughing, difficulty breathing, and inflammation and irritation of the respiratory tract, to the development of lung or heart disease and premature mortality.
Last year marked the 40th anniversary of the Clean Air Act, one of the first environmental laws designed to minimize threats to public health and welfare. To comply, EPA sets air emissions standards for the six most common “criteria” pollutants: ozone (O3), particulate matter (PM10 and PM2.5), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and lead (Pb). Since local air quality improvement programs began, concentrations of these pollutants have dropped in the District and surrounding areas.
Even so, the American Lung Association’s 2011 “State of the Air” report listed the Washington region as the 14th most polluted metropolitan area for ground-level ozone. The District currently complies with all of EPA’s air quality standards except for ground-level ozone, or smog. Pollutant levels in the District compared with the Clean Air Act standards are presented below. (Pb levels are not included in the chart because they are especially low.)
Ozone is a colorless, odorless gas that exists naturally in the Earth’s upper atmosphere, where it shields the Earth from the sun’s ultraviolet rays, but it is also found close to the Earth’s surface where we live and breathe. “Ozone season” in the Washington, DC, region, when photochemical reactions that form ozone are most likely to occur, is between May and September.
In the District, air pollutants are primarily emitted by motor vehicles. Other sources include large and small boilers and generators that burn fuel to service buildings, construction and lawn maintenance equipment, the use of paints and adhesives and other commercial and consumer products, as well as fumes from gasoline stations, dry cleaners, printing stores, restaurants, and the like.
Air pollution is also “transported” into the area from the operation of power plants and industrial and manufacturing facilities in upwind states. For example, earlier this year, Mayor Gray expressed concern about the transport of pollution from a facility in Virginia into Ward 8, where asthma rates are amongst the highest in the nation. Shortly afterwards, decades-long pressures to close the Potomac River Generating Station, a coal-fired power plant located in Alexandria, were concluded. Plant operations will likely cease in 2012.
DDOE’s Air Quality Division monitors the ambient air quality at several locations in the District. That information is compared to air quality standards to develop long-term air quality improvement strategies. Vehicle emissions inspections and maintenance program and air pollution emission limits on stationary sources through permitting are examples of control measures the District has put in place in the recent years.
Will the air quality continue to improve in the coming years? Very likely. As EPA continues to tighten the standards for common pollutants, cooperation amongst states and regions to develop innovative solutions will become increasingly critical.
Jessica Daniels is an Environmental Protection Specialist in the Air Quality Division at the District Department of the Environment.