WASHINGTON – The number of bad ozone days decreased in the Baltimore- Washington region from 1999 to 2000, even as another dangerous pollutant in the region remained higher than national standards.
The Environmental Protection Agency said that the number of days during which the ozone levels exceeded national standards dropped from 40 in 1999 to 16 in 2000 in Baltimore, and from 39 to 11 in Washington.
But the October report also said that fine particulate matter — air pollutants that have been linked to significant health problems for high-risk groups — has consistently been recorded at levels above national air quality standards at Maryland monitoring sites.
EPA spokesman Dave Ryan said the fine particulate matter is probably more dangerous than other pollutants such as soot or dust, because their small size allows them to pass through the body’s natural filters. “It gets into lungs more easily,” he said.
Fine particulate matter includes secondary pollutants formed in the atmosphere from primary pollutants, such as car and power plant emissions.
High levels of fine particulate matter could become a significant problem, EPA officials said, but the agency still needs at least one more year of data before it can make an assessment of the scope of the problem.
The EPA’s preliminary data shows that Maryland is probably exceeding the national standards for particulate matter, but nothing official will be done until the data is finished being collected and analyzed, said Randy Mosier, an air quality planner for the Maryland Department of the Environment.
Ozone pollution, by contrast, has been studied much longer and is much better understood.
Ozone, a chief component of smog, naturally occurs in the upper levels of the atmosphere, but it is dangerous when it is at ground level. Mosier said the 2000 drop in the region’s ozone levels came mostly because the weather was cooler, but that stricter regulations have driven down levels over the long run.
“We are seeing a significant decrease in the amount of days that we would typically violate the standard since the 1980s,” Mosier said. “A lot of it can be largely attributed to the regulations in place to offset emissions.”
Mosier said fine particulate matter is high in Maryland because of the number of factories, cars and other vehicles here, as well as smokestack emissions from the highly industrial Ohio Valley that drift to the East Coast.
Frank O’Donnell, executive director of the Clean Air Trust, said the increasing amount of these pollutants is a growing problem that states need to address.
“Fine particulate causes an array of health problems ranging from exacerbating asthma . . . to just general difficulty breathing, to premature death,” he said. “There have been studies that link it from 50,000 to 60,000 premature deaths a year.”
O’Donnell said that the problem stems mostly from power plants, trucks and buses and largely unregulated non-road diesel vehicles such as bulldozers and tractors.
“It’s a growing problem and I think we are still not sure how great the problem is because all the monitors are not up and running yet,” he said. “It will be a dominant concern in air quality in the future.”
But industry groups say that fine particulate matter pollution will likely begin to decrease, as other pollutants have decreased over the past several years.
“Air quality trends have been improving quite consistently and substantially over the years,” said Dan Riedinger, a spokesman for the Edison Electric Institute. “It (fine particulate matter) over time, as well, will show to be decreased with the other types of emissions.”
Riedinger said fine particulate levels should drop significantly as the second phase of sulfur dioxide emissions reductions gets under way.