Air quality has improved a lot in Maryland and nationwide over the past 15 years, according to a new report, but summertime smog levels in Harford and Prince George's counties are still among the worst in the country.
Despite strides made virtually everywhere in reducing soot or particle pollution, nearly half of all Americans still live in places where smog or soot pollution makes it dangerous to breathe at times, the American Lung Association reported Wednesday in its 15th assessment of the nation's air quality.
Maryland earned a passing grade from the health group for limiting residents' chronic exposure to particle pollution, which can cause respiratory and heart problems, and has been linked both to cancer and premature death. But improvements notwithstanding, the state got failing marks for the number of days when people outdoors were forced to breathe levels of ozone pollution, also known as smog, that could trigger asthma attacks or heart attacks.
Indeed, the lung association noted that in 22 of the 25 metro areas with the worst ozone pollution - including the Washington-Baltimore region - there was an uptick in smog from 2010 through 2012, when compared with the prior three years. The group assessed multi-year averages to adjust for variability in weather, which can heavily influence ozone and particle pollution.
Harford had the 13th worst ozone levels of any county in the nation, and Prince George's ranked 21st. At the same time, the lung association rated Harford as being among the 25 "cleanest" counties when it comes to particle pollution.
Janice Nolen, chief author of the lung association report, said the unusually hot summer of 2012 drove smog levels higher that year in Maryland and elsewhere. Ozone forms when vehicle exhaust, power plant emissions and other pollutants "cook" in the lower atmosphere under hot, sunny conditions.
By comparison, during last year's unusually cool summer, Maryland experienced just nine days when ozone reached levels unsafe for vulnerable individuals, the fewest registered in the state since 1980. During the blistering 2012 summer, there were 30 days when smog reached dangerous levels.
Nolen said the worse smog levels in 2012, while weather-related, posed a warning about how pollution could be worsened by climate change, which is expected to bring more heat waves.
"It was raising our awareness about ... how hard it's going to be fighting ozone if we've got to battle climate change," she said. The lung association favors tightening limits on carbon dioxide emissions in addition to curbing smog and soot emissions, Nolen noted.
While smog remains a problem in Maryland, the bulk of its ozone pollution is beyond the state's control, said George S. "Tad" Aburn, director of air management for the Maryland Department of the Environment.
"We're pushing like crazy with every tool we have," Aburn said, "but on any given day, depending on the weather, 70 to 90 percent of our problem with ozone comes from other states." Still, he acknowledged that while Los Angeles remains the undisputed smog capital of the U.S., ozone pollution levels in Harford remain the highest in the East.
For that reason, he said, state officials have pressed the Environmental Protection Agency to crack down on emissions of power plants in neighboring states and even as far away as Ohio and Illinois, which contribute to Maryland's pollution. Aburn welcomed the Supreme Court's decision Tuesday upholding the EPA's authority to regulate emissions that drift across state borders, calling it "a way to move forward."
Meanwhile, Aburn said, state officials aren't relying solely on federal action. The state is eyeing imposing new limits on some of its smaller, dirtier coal plants, he said, and Maryland has joined with seven other states in seeking to promote "zero emission" vehicles, including electric cars.
"We are continuing to move ahead," Aburn said, "adopting regulations that make sense."