The Ehrlich administration stopped monitoring ozone pollution in Baltimore almost three years ago, despite the city's chronically bad air and the presence of the state's largest concentration of people with asthma.
The Maryland Department of the Environment decided that keeping the monitors in the city is a waste of money because the state maintains six others in the surrounding suburbs, according to the agency.
"You don't need to have a monitor on every corner to know that the air in one place isn't as clean as in another place," said Richard McIntire, an MDE spokesman.
The Baltimore area has a long history of failing to meet federal air quality standards. Many metropolitan areas with similar problems - including Washington, Philadelphia, Boston, New York, Houston and Chicago - have ozone monitors both in the cities and in the surrounding suburban areas, according to officials in those areas.
Baltimore's health commissioner, Dr. Joshua Sharfstein, and some environmentalists say that ozone in the city requires continued monitoring because pollution is sometimes worse in urban areas than in the suburbs, and failing to measure in the city could distort the state's air quality reporting.
The growing number of people in Baltimore with asthma - 46,318 at last count - deserve to know when they're at risk of hospitalization because of high ozone levels, Sharfstein said.
"You've got the No. 1 air pollution problem in the state, and the No. 1 location in Maryland for asthma, which is linked to ozone," Sharfstein said. "How could they not be monitoring for ozone in Baltimore City? They should not be ignoring the largest city in Maryland."
Ground-level ozone, the main ingredient in smog, forms when vehicle exhaust, power plant pollution and other fumes combine in bright sunlight on hot summer days. The gas irritates lung tissue, causing asthma attacks and permanent lung damage.
Bill Becker, executive director of the State and Territorial Air Pollution Program Administrators, a Washington-based nonprofit group that represents government environment officials from around the country, said eliminating all ozone monitors in Baltimore could make data about the area's air quality less accurate.
"If it's zero monitors in the city, then there are potential problems in that the public deserves to know whether the air they breathe is safe," Becker said.
The number of summer days in which Maryland's air violated a one-hour federal ozone standard had been slowly falling over the years, with 17 in 1991 and 11 in 1999. But the figure dropped sharply in 2003 - when the MDE stopped monitoring ozone in the city. The figure went from 14 bad-air days in 2002 to two days in 2003, one in 2004 and three last summer, according to state figures.
MDE attributes this drop to improving weather conditions. Michael Woodman, a meteorologist with the agency, pointed out that 2002 was an unusually hot summer, with 48 days above 90 degrees; 2003 was cooler, with 14 days in the 90s.
But critics suggest that a lack of ozone monitors in the city might also be skewing the state's air pollution data.
The state maintained at least one, and sometimes two, ozone monitors in the city every summer from 1983 to 2002, with one gap in 2000 because of vandalism. The monitors were placed at five sites at different times. One was at Lake Clifton School in East Baltimore; another was beside the Inner Harbor.
The city monitors often measured ozone levels above federal standards, according to state data. The sensors were part of a statewide system that now includes 16 monitors from Western Maryland to the Eastern Shore and costs about $2.5 million a year to operate.
Rena Steinzor, co-director of the University of Maryland Environmental Law Clinic, said shutting down all the ozone monitors in Baltimore is "outrageous" and suggests MDE might be trying to make air pollution levels look lower than they really are.
Maryland officials might want to reduce the number of monitors as a shortcut to meeting federal ozone standards - a measurement the government uses to determine who gets millions of dollars in highway funds, Steinzor said.
"They are cheating," Steinzor said of the MDE. "Ozone monitors are the foundation of the whole system. Without them, we never know where we are, and we can never tell if we are making progress on air pollution. Ozone exacerbates asthma, and asthma is epidemic in the city, especially among children."
David Krask, chief of air monitoring for the state environmental agency, said monitors in suburban Harford, Carroll, Baltimore and Anne Arundel counties are adequate to let officials know when they should warn Baltimore residents that ozone levels are dangerous.
