Environmental▼News Den, senior science adviser for EPA’s Region 9. An aggressive sampling campaign requires stirring up the ground and sampling at the breathing zone level. For example, when technicians used a tractor rake to drag the baseball infield and the dirt track surrounding the football field of the local Oak Ridge High School in July, some results exceeded worker safety exposure limits. In August,
the school’s football stadium and baseball diamond were closed, and they have yet to be reopened. Scientists interviewed for this story and many citizens worry that local authorities fail to realize the magnitude of the problem and that federal authorities can’t act because they believe they don’t have jurisdiction over a naturally occurring problem.
No one wants a repeat of what happened in Libby. A May 2003 General Accounting Office report criticized EPA for underestimating the extent of contamination in Libby when citizens first complained in 1982. EPA only began an extensive investigation and cleanup after media reports called attention to the health disaster, according to the report. —REBECCA RENNER
Independent, long-term study shows regulations and technology cut vehicle emissions tenance programs, which generally exempt newer cars. Changes in gasoline formulation also cannot explain the factors of 3 or 4 differences in emissions that they found, the researchers say. The only explanation left is that the combination of federal mandates and the auto manufacturers’ improved ability to meet these mandates has made emission control devices more reliable over longer time periods, says Stedman. DONALD STEDMAN
The first independent, long-term, on-road analysis of tailpipe emissions from newer cars and light-duty trucks shows these vehicles emit less pollution over time than older vehicles, according to research in the Nov 15 issue of ES&T (pp 5097–5101) from the University of Denver. The researchers assert that four decades of federal regulations have successfully prodded automotive manufacturers to improve the performance and durability of their emissions control technology. In other words, car designers are getting better at creating more durable emissions reduction technology every year. For the past 13 years in Denver and 5 years in Los Angeles and Chicago, Donald Stedman’s group, which pioneered on-road sensing, has measured carbon monoxide (CO), hydrocarbons, and nitric oxide (NO) in vehicle emissions near off-ramps of major thoroughfares. The subset of data discussed in the ES&T paper was collected from 1997 through 2001 on vehicles less than four years old. It demonstrates that each succeeding model in its first year emitted less pollution than the previous year’s models in their first year—even during a period when regulations remained static. For example, the researchers found that in the cars they analyzed in Denver, emissions of CO, hydrocarbons, and NO decreased an average of 12%, 7%, and 16%, respectively, each year. By looking only at emissions of new vehicles, the researchers ruled out effects of inspection and main-
This four-year-old vehicle is an example of on-road emissions testing by Stedman’s group. Date and time are listed across the top of the image, and carbon monoxide, hydrocarbon, nitric oxide, and carbon dioxide readings, respectively, across the bottom.
Experts agree. Brett Singer, a Lawrence Livermore National Laboratory engineer who has worked on emissions studies, says that “certification tests don’t tell us what is really happening on the road,” whereas this study underscores “the on-road effect of all these standards we are putting in place.” Louise Bedsworth, a senior analyst at the Union of Concerned Scientists, a nonprofit organization, says the research shows that manufacturers
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are taking more responsibility. How will these results impact future policy making? Opinions vary. Joel Schwartz, a senior fellow at the Reason Public Policy Institute, a public policy think tank, believes that the Tier 2 regulations, which require the same emissions limits for light trucks as for cars and take effect for the 2004 model year, are sufficient for the future. He says that even without Tier 2 or additional regulations, emissions would decrease at least 85%, despite people driving more. “It means that fleet turnover will eliminate most of the remaining emissions from automobiles during the next 20 years or so.” On the other hand, Bedsworth adds that regulations can do more to further reduce air pollution. Reflecting on the progress that has been made is important, she says, but we cannot run the risk of “resting on our laurels.” Stedman renews his longtime call to simply get the “gross polluters”—the small percentage of older, poorly maintained cars that emit more than half of the automotive pollution—off the road now. Gross polluters of CO now compose only 6% of the fleet in Denver, down from 9% in 1989, but the cars still on the road expel an average of 480 grams of CO per kilogram of fuel or 32 times the median. “When we started out 13 years ago, 1 car in 10 was putting out more emissions than the other 9 put together, and we are now at 1 car in 20,” Stedman says. “Shouldn’t we be spending our money dealing with that one rather than making everyone spend more money on new cars?” —RACHEL PETKEWICH
