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Growing Old and Polluting the Air
Air Quality Laboratory monitors emissions of an aging vehicle fleet.
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People are driving their vehicles into the ground. This is
good for the family budget, but not so good for air quality. As vehicles
age, their emissions control systems become less efficient, and the
vehicles release more pollution.
photo
by Jane M. Sanders
Georgia Tech researchers,
including Alex Samoylov, use remote sensing equipment at highway
entrance and exit ramps in Atlanta to monitor vehicle emissions.
These are some of the findings of a long-term vehicle
emissions monitoring program conducted in Atlanta since April 1993 by
Georgia Tech's Air Quality Laboratory.
The Georgia Department of Natural
Resources has funded the research with about 25 cents of the $25 vehicle
emissions inspection fee charged per vehicle in metro Atlanta.
"Previously, there was not a systematic methodology for determining
the effect of aging on a vehicle fleet over time with on-road
measurements," says Dr. Michael Rodgers, director of the Air Quality
Laboratory. "The Atlanta study is now the oldest monitoring program of
its type in the world."
The Air Quality Laboratory also conducts similar short-term studies
across the nation to complement the findings of the Atlanta monitoring
program. These studies, funded by the U.S. Environmental Protection
Agency, have been conducted throughout much of the eastern United States
(including New York City, Boston, Baltimore, Nashville and Raleigh) and
are planned for parts of Oregon, Utah and California.
Using remote sensing, vehicle registration data and roadway
observation studies, researchers now know that the average vehicle in
Atlanta has about 90,000 accumulated miles on it, and that there are a
significant number of vehicles with more than 200,000 miles on them.
Knowing this information gives insight into the city's ozone pollution
problems.
In General....
In Atlanta....
• A 1997 study by the U.S. Environmental Protection Agency found
that Atlantans had the longest average commute of any city in the world
— 34.7 miles a day. Some people commute more than 120 miles a day
round-trip.
• Atlanta's traffic congestion costs more than $1 billion a year
in delays and wasted fuel, according to the Texas Transportation
Institute.
• The Sierra Club reported last year that Atlanta faces the worst
urban sprawl problem among cities of more than 1 million in population.
On average, 500 acres of green space, forests and farmland disappear in
the Atlanta metropolitan area each week, the study said.
Elsewhere....
— Cities of 1 million or more people (20): Atlanta, St. Louis,
Washington, D.C., Cincinnati, Kansas City, Denver, Seattle,
Minneapolis-St.Paul, Ft. Lauderdale, Chicago, Detroit, Baltimore,
Cleveland, Tampa, Dallas, Hampton Roads, Va., Pittsburgh, Miami, San
Antonio, Riverside-San Bernardino, Calif.
— Cities of 500,000 to 1 million people (5): Orlando, Austin,
Tex., Las Vegas, West Palm Beach, Fla., Akron, Ohio.
— Cities of 200,000 to 500,000 (5). McAllen, Tex., Raleigh,
N.C., Pensacola, Fla., Daytona Beach, Fla., Little Rock, Ark.
— The Sierra Club did not include Los Angeles in its ranking,
although it said the city is acknowledged to be "the granddaddy of
sprawl." "Los Angeles stands as a warning of why not to sprawl," the
report's authors wrote.
"As vehicles get older, there is degradation," Rodgers says. "Most
vehicles gradually increase their emissions, but there are some
catastrophic failures, such as holes in catalytic converters."
Fuel-injected vehicles manufactured since the mid-1980s tend to
deteriorate more slowly than the previous generation of vehicles,
Rodgers says. 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, Rodgers explains.
Emissions inspections presumably detect vehicles with catastrophic
failures. In reality, however, only 1 percent of vehicles manufactured
in the past six years has failed an emissions test. "It's like looking
for a needle in a haystack," Rodgers says. But the search is worth it
because vehicles with catastrophic emissions systems failures can be
responsible for 50 to 70 percent of emissions.
Vehicle Data Collection
In roadway observations, researchers determine the total emissions
released on a particular roadway. For example, a recent study was
conducted on Interstate 20 near Bremen, Ga. Researchers measured
emissions from commercial trucks overnight. They monitored emissions and
weather conditions both upwind and downwind.
The Air Quality Laboratory also conducts vehicle tests in its new
dynamometer lab, which was donated to Georgia Tech earlier this year by
Atlanta Gas Light Company. There, researchers determine when and why
vehicles release high and low amounts of emissions. This detailed
information complements the less-detailed data gathered in remote
sensing studies. Researchers also conduct dynamometer equivalent tests
on vehicles they purchase and equip with emissions instrumentation.
"Georgia Tech is one of a very few places in the United States to do
both remote sensing and dynamometer testing," Rodgers says. "So we
probably have the most comprehensive, university-based vehicle emissions
testing program in the country."
— Jane M. Sanders
• Motor vehicles create 50 to 70
percent of air pollution problems in metropolitan areas, according to
Georgia Tech researchers.
• Atlanta commuters spend 69 hours annually or nearly nine
workdays a year in traffic, according to a recent report by the Texas
Transportation Institute, which studies the country's most congested
roadways.
• According to the Sierra Club, these
are the cities with the worst urban sprawl:
The Air Quality Laboratory uses both remote sensing and roadway
studies to obtain its data. In remote sensing studies, researchers
gather vehicle information at entrance and/or exit ramps. In just
seven-tenths of a second, remote sensing equipment measures a vehicle's
emissions as it breaks an infrared beam in its path. Other equipment
photographs the vehicle's tag; researchers later use this photo to
correlate emissions data with registration data.
For the full text news release,
see
www.gtri.gatech.edu/res-news/EMISSION.html.
For more information, contact Dr. Michael Rodgers, Air Quality
Laboratory, Georgia Institute of Technology, Atlanta, GA 30332-0355.
(Telephone: 404/894-5609)
(E-mail: michael.rodgers@eas.gatech.edu)
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Last updated: May 28, 1999