Older cars make for dirty air

Georgia Tech researchers use remote sensing equipment at highway entrance and exit ramps in Atlanta to monitor vehicle emissions

May 20, 1999
Web posted at: 1:30 PM EDT

Older cars in Atlanta, Ga., are responsible for upwards of 70 percent of the region's automobile-related air pollution, according to six years of emissions data collected on more than 2 million vehicles.

"Atlantans drive more per day and keep their vehicles longer than drivers in many other major U.S. cities, particularly those in the north where vehicles don't last as long because of salt on the roads," said Michael Rodgers, director of Georgia Tech's Air Quality Laboratory.

"Our concern is that we expect this trend to continue, and as vehicles get older, there is degradation. Their emissions control systems become less efficient and the vehicles release more pollution into the air," he said.

The average vehicle in Atlanta has about 90,000 miles on it and there are a significant number of vehicles with more than 200,000 miles on them, according to the laboratory.

Rodgers and his research team are entering their seventh year of a long-term vehicle emissions monitoring program of Atlanta and short-term studies in other eastern U.S. cities.

The researchers use remote sensing, vehicle registration data, roadway observation studies and laboratory testing to compile emissions data that provides insight into ozone pollution problems.

Short-term studies conducted in New York City, N.Y.; Boston, Mass.; Baltimore, Md.; Nashville, Tenn.; and Raleigh, N.C.; complement the findings of the Atlanta monitoring program. Further studies are planned for parts of Oregon, Utah and California this year.

"Most vehicles gradually increase their emissions, but with aging vehicles, there are some catastrophic failures, such as holes in catalytic converters," said Rodgers.

Fuel-injected vehicles manufactured since the mid-1980s tend to deteriorate more slowly than the previous generation of vehicle, said Rodgers. But people are driving their vehicles longer now, even in excess of 300,000 miles. So Atlanta can expect to see an increase in catastrophic failures in vehicle emissions control systems as its fleet ages, he said.

The research is funded by the Georgia Department of Natural Resources and the U.S. Environmental Protection Agency.

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