Smog has reached unhealthful levels in Maryland far more often this summer than state and federal officials have led the public to believe, a University of Maryland researcher said today.
Dr. Rebecca Bascom, a pulmonologist at UM's School of Medicine, said state air monitoring data indicate that ground-level ozone concentrations in the Baltimore metropolitan area are high enough to cause health problems on three times as many days as the Maryland Department of the Environment has reported.
The state, relying on an air-quality standard set by the U.S. Environmental Protection Agency, says that ozone has reached unhealthful levels around Baltimore on 12 days so far this summer, making this one of the worst since 1983. On such days, the state advises people with respiratory or heart ailments to stay indoors.
But recent research has shown that even healthy children and adults suffer lung inflammation and breathing difficulties from inhaling what officially are only "moderate" ozone levels in the air, Bascom said.
Citing that research, health and environmental groups and five smog-plagued Northeastern states called on the EPA today to tighten its air-quality standard for ozone.
The American Lung Association said that ozone concentrations in 182 metropolitan areas, including Baltimore, Cumberland and Washington, now exceed levels shown by studies to cause health problems. The association and the other groups threatened to sue EPA if the agency does not move quickly to revise its health standard for ozone.
Peter Baijet of the lung association said that EPA's current health standard for ozone "underestimates the extent and seriousness of the smog problem, and that a review of the science will indicate the need for revision."
Ozone is an invisible gas produced by mixing volatile organic compounds and nitrogen oxides, both of which are given off by cars and factories.
The federal standard now says that ozone concentrations of 120 parts per billion for an hour constitute a health threat.
Martha Casey, an EPA spokeswoman, noted that the agency's Science Advisory Board, a panel of outside experts, concluded two years ago that there was insufficient evidence of health effects to justify lowering the federal air-quality standard for ozone.
Over the past three or four years, however, several studies have been published in which healthy adults and children suffered harmful effects from breathing ozone concentrations of as little as 80 parts per billion for six to eight hours. They experienced coughing and wheezing fits, chest and throat pain.
Researchers also have found evidence of lung inflammation in people exposed to ozone levels of 80 parts per billion, indicating they may suffer chronic lung damage.
An analysis of state air-monitoring data for last month performed by Katrina Barnett, a student researcher at UM, indicates that ozone reached such levels somewhere in Maryland during 40 percent of normal "waking" hours, between 8 a.m. and 10 p.m.
The worst ozone problems seem to occur in the suburbs rather than the city, Bascom said.