Maryland Department of the Environment
Last year, the state met three federal standards for reducing ozone and fine-particle levels and we are on the cusp of meeting a fourth. Air toxics have been cut nearly in half in the past decade. Carbon monoxide and lead have been virtually eliminated from the air.
To meet the requirements of Maryland's landmark Healthy Air Act, the largest coal-burning power plants have installed "scrubbers" to remove pollutants. The Healthy Air Act -- the most sweeping air pollution program ever in Maryland and the toughest power plant emission law on the East Coast -- requires reductions in emissions of nitrogen oxide, sulfur dioxide and mercury. The Maryland Clean Cars Program includes standards for model year 2011-and-later vehicles that significantly reduce volatile organic compounds and nitrogen oxide emissions (along with greenhouse gases that contribute to climate change). The federal government is working toward tougher standards for power plants in other states and for industrial boilers, cement kilns, and motor vehicles.
In the 1970s and 1980s you could routinely see and smell air pollution in Maryland, but the Clean Air Act amendments of 1990 set the stage for change. After steady but slow improvement early on, air quality has dramatically improved over the past six years.
Volatile organic compounds (VOCs) are released into the air when we drive and use such products as fuels, paints, household cleaners, and personal hygiene products. Nitrogen oxide (NOx) is emitted when fossil fuels are burned. These compounds form ground-level ozone when cooked by the sun. Breathing ozone can cause respiratory problems. NOx deposits contribute approximately one-third of the nutrient pollution in the Chesapeake Bay.
Sulfur dioxide is produced by the burning of fossil fuels containing sulfur compounds. It is the most significant contributor to the problem of fine particles, which creates haze that decreases visibility and is linked to premature death and heart and lung problems.
Maryland's weather and geography are also factors. Power plant pollution from the Ohio River Valley rides the wind into Maryland, while Chesapeake Bay breezes act as a wall of cool air that concentrates pollution along the Interstate-95 corridor. On certain days, southerly winds carry pollution that is funneled into Maryland by the Appalachian Mountains to the west and the Atlantic Ocean to the east.
At certain times, as much as 70 percent of the pollution in our air comes from other states. To address this, Maryland is part of the multi-state Ozone Transport Commission, which works to implement regional requirements. We have pressed EPA to propose stringent new controls, in part, because the reductions are needed and, in part, because it is a matter of fairness. All power plants should have to do what Maryland's plants are already doing. We need to also emphasize the importance of strong national requirements for emission reductions in improvements to the Chesapeake's water quality. Maryland will continue to press for tougher national and regional standards.
With the advent of summer -- when air pollution levels typically peak -- you too can help. This summer, our meteorologists tell us we can expect more ozone action days than last summer. Please visit MDE's website for three-day air quality forecasts, sign up for email alerts or call the air quality hotline at 410-537-3247.