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As the next-day forecast warned of temperatures soaring toward triple digits, a monitoring station on a Garrett County mountaintop registered high levels of pollution in the nighttime air high above Maryland’s western gateway.
By the following afternoon, much of the state was contending with some of the worst air quality in years.
Hot and sunny weather can cook emissions in the air to form ground-level ozone pollution, and this summer has presented a series of heat waves. But while Maryland has seen a number of bad air days this year, the problem would be much worse if not for the steps taken in recent years to reduce pollution.
What’s more, the results from that Western Maryland monitoring station in the wee hours of June 29 demonstrate that under certain weather conditions much of this pollution comes from other states.
Overall, the quality of Maryland’s air has increased dramatically in recent years due to programs such as the Maryland Healthy Air Act, the toughest power plant law on the East Coast, and the Clean Cars program, which requires stricter California standards for vehicle emissions. The percentage of good and moderate air days has increased steadily while the percentage of bad air days has gone down. More than 91 percent of days last year were good or moderate for air quality.
Through August 6, there were 25 days this year in which readings from at least one of Maryland’s 18 monitoring stations exceeded air quality standards for ozone. Most of those days showed “code orange” levels, meaning the air was unhealthy for sensitive groups such as children, the elderly and people with respiratory or heart ailments. Three days included readings of “code red” – unhealthy for everyone – from at least one monitoring station. There were a total of 27 code orange days in 2011, and 43 in 2010.
To understand and predict air quality conditions, MDE scientists analyze weather patterns and review air quality conditions in other states. They also examine monitoring results obtained through special research airplane flights, weather balloon launches and readings at air monitoring stations such as the Piney Run location in Western Maryland.
On June 28, MDE saw very high levels of ozone, or smog, in the Ohio River Valley. When day turns to night, ozone levels typically drop. But at Piney Run – in an area of the state with relatively few air pollution sources – the levels stayed above code orange through the overnight hours. To MDE experts, this was a clear sign of ozone “transport” – pollution from sources such as power plants blowing in from out of state.
What followed was Maryland’s worst air quality day of the year by far. On June 29, readings at all 18 of Maryland’s monitoring stations exceeded the standard for ozone, and 10 stations registered “code red.” A station on the Eastern Shore showed the worst readings – approaching “code purple,” a level considered very unhealthy for everyone.
With as much as 70 percent of Maryland’s air pollution coming from upwind states, MDE is working toward stronger federal and regional air control standards. At the same time, MDE continues to work to reduce pollution generated locally.
MDE encourages everyone to be informed. You can call the Department’s air quality hotline at 410-537-3247 for conditions. For air quality forecasts, go to www.cleanairpartners.net or follow MDE on twitter @MDEnvironment.
There are many steps we can all take to help make our air cleaner. These include postponing mowing the lawn or painting on bad air days and limiting driving by carpooling, using public transportation or working from home, if possible. The Clean Air Partners website includes a list of tips to make our air cleaner.
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