Older Cars Fouling Region's Air Quality
Agency Study Links Recession, Pollution

By Katherine Shaver
Washington Post Staff Writer
Saturday, July 4, 2009

The recession is contributing to higher levels of air pollution in the Washington area as new car sales plummet and older, dirtier vehicles remain on the road longer, according to a recent study by regional planners.

The trend is expected to show up across the country as transportation planners use vehicle registration data collected after the economy soured to adjust local air quality forecasts required by federal law. The Metropolitan Washington Council of Governments is believed to be the first planning agency to analyze that data.

Vehicles on the road in the Washington area are an average of six months older than they were in 2005. The increase, from about 7.9 to 8.4 years, is enough to push the region perilously close to violating its limits for traffic-related pollutants, according to the study.

"If you trade in a 1995 Jeep Cherokee for a new one, that's a big difference in emissions," said Ronald F. Kirby, COG's transportation planning director. "We can't keep emissions going down unless we get newer vehicles in the fleet."

Last month, President Obama signed "cash for clunkers" legislation that will provide as much as $4,500 to people who trade in older, less fuel-efficient vehicles to buy or lease ones that get better gas mileage. The measure, which some critics said does not do enough to cut carbon emissions, is intended to help the auto industry while putting cleaner cars and trucks on the road.

In the Washington area, tailpipe emissions next year will be as much as 7.5 percent higher than projected in forecasts conducted last year, according to COG's analysis. The increase in vehicle age overwhelmed changes friendly to the environment, such as an increase in hybrid vehicles and a move away from gas-guzzling sport-utility vehicles toward smaller and relatively fuel-efficient passenger cars, the study found.

Kirby said he was particularly troubled that aging vehicles are predicted to cause increased emissions even as motorists are expected to cut their driving by 2.5 percent, in part because of higher unemployment. The finding is at odds with a basic tenet of transportation planning, that tailpipe emissions drop when people drive less.

Rich Denbow, director of technical programs for the Association of Metropolitan Planning Organizations, said the COG study is the first in the country to document the connection between older vehicles and worsening air pollution. However, Denbow said, he expects other areas will find the same problem when they update their air quality forecasts.

"We're the first ones to see it, but I think it will be a national issue," said Denbow, whose organization is based in the District. "Our economy is better than a lot of others, so the [older vehicle] problem isn't as bad here as it will be in other areas."

Michael Replogle, transportation director for the Environmental Defense Fund, said he is concerned that the problem is even worse than COG projected. The computer models that Kirby's staff used have been found to project less pollution than a newer model that planning agencies will begin using in the near future, he said.

Transportation planners said they hope new car sales will rebound as the economy does, but Replogle said he thinks the nation's vehicle fleet will remain on the older side because so much shopping in recent years was fueled by cheap credit.

This is a critical time, transportation planners said, because tighter limits on tailpipe emissions took effect in 2004 and 2007. Having an average vehicle age of more than eight years means that many of those on the road are higher-polluting.

"We're at a point now that when an older vehicle turns over, we see dramatic improvements" in pollutants, Kirby said. "How can you expect us to meet our targets for emissions when we have no control over the economy and the rate at which people buy new vehicles?"

Kirby said computer models most recently showed that volatile organic compounds are predicted to increase an additional 6.6 percent and nitrogen oxides an additional 7.5 percent in 2010, when compared with last year's forecasts. The two pollutants contribute to unhealthy levels of ground-level ozone that on Code Red days prompt public officials to advise the elderly, children and people with respiratory or heart problems to remain indoors.

Fine particulate matter, a pollutant that can cause serious health problems when it gets into the lungs and bloodstream, is expected to increase an additional 1.3 percent over last year's predictions, the COG study found.

The federal Clean Air Act requires metropolitan areas to show that they will remain within their pollution limits when emissions from existing traffic are combined with those forecast to come from future road and transit projects. Exceeding those limits can cost a region money for new transportation projects. The Washington area is required to reduce emissions from vehicles, power plants and other sources because it has failed to meet federal ozone standards for decades.

Kirby said his staff began paying closer attention to the vehicles on local roads after they discovered 10 years ago that the growing popularity of SUVs and the increase in miles driven could cause the region to violate its emissions limits. To prevent the loss of federal transportation funding, Washington area local governments have spent $38 million this decade to curb exhaust-related pollution.

The region won't exceed its limits for traffic-related pollutants in 2010, Kirby said, but the computer models showed it will come "within an eyelash" of doing so.

Joan Rohlfs, chief of air quality planning for COG, said she is most concerned about pollution from diesel trucks, which emit the dirtiest exhaust and are driven longer than passenger cars.

"Anything that contributes to pollution is not good for anyone's health," Rohlfs said.

The number of hybrid vehicles in the area jumped to 41,729 in 2008, from 11,843 in 2005, but they still make up a minuscule percentage of the overall fleet. Hybrids account for 1.5 percent of vehicles on Northern Virginia and District roads and 0.8 percent on roads in the Maryland suburbs, according to the COG analysis.