Carnegie Mellon researchers apply new statis...( PITTSBURGHCarnegie Mellon Universit...)

PITTSBURGHCarnegie Mellon University's Cliff I. Davidson, Joseph B. Kadane and Nanjun Chu have found that polluted air in the highly populated East End areas of Pittsburgh are more affected by major sources to the city's southeast than previously thought.

Because more than three-quarters of particulate matter found in the city originates from outside the Pittsburgh urban area mainly to the west the importance of certain air quality sources had not been quantified in the past.

However, the new study shows that the most polluted days often occur when the winds are from the southeast, when emissions from the U.S. Steel plants add to the regional background to raise PM (particulate matter) levels over the National Air Quality Standard.

"Those southeast winds are helping pollutants from the Clairton and Edgar Thompson works hitch a ride right into our backyards," said Davidson, a professor of civil and environmental engineering and engineering and public policy at Carnegie Mellon.

Pittsburgh's history and buildings are stained with soot from steel and coal-burning home furnaces and locomotives, but pollution controls over the past decade have helped remove much of the visible dust and soot from the air. Still, interest in tiny, almost invisible PM2.5 particles ballooned in the early 1990s, when studies showed a correlation between these particles and dangerous health effects, including respiratory problems.

In last month's prestigious Environmental, Science & Technology magazine, Davidson's research team said that by using statistical methods incorporating wind speed and wind direction at 10-minute intervals for a full year, they can help track the source of PM2.5. Their research also found that the number of days when concentration exceeds 35 micrograms of PM2.5 per cubic meter of air in the city's Squirrel Hill/Oakland areas was four times higher than the number of days allowed by the National Ambient Air Quality Standard admi
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