AUTO EMISSIONS DECLINE IN MAJOR U.S. CITIES

A nonprofit transportation group has pinpointed U.S. cities' progress in reducing auto emissions.

A report issued by The Road Information Program (TRIP), Washington, shows that Seattle, Sacramento, San Jose, Phoenix, Denver, Minneapolis, Kansas City, Dallas, Charlotte, and New York were the top 10 major cities in which air quality improved the most during 1984-93.

TRIP analyzed air quality data from the U.S. Environmental Protection Agency from 1984 through 1993, the last year for which figures are available. Overall, the number of poor air quality days in the top 85 major urban areas declined by two thirds.

"Air quality improvements have been taking place throughout the country for more than two decades," said William M. Wilkins, TRIP executive director.

The report also said the nationwide decline in motor vehicle emissions took place at the same time highway travel increased by nearly 34%.

"The main reason air quality improved is that cleaner burning fuels and cars are bringing about significant reductions in motor vehicle emissions," Wilkins said.

TRIP said nationwide highway vehicle emissions of volatile organic compounds declined 35.5%, nitrogen oxides 11.3%, and carbon monoxide 24% during 1984-93.

The report also analyzed the cost effectiveness of several methods used to reduce motor vehicle emissions.

These fall into two main areas: technological and behavioral.

The technological group includes things such as catalytic converters, engine and exhaust systems, and cleaner burning fuels.

Among behavioral strategies are changes in driving such as carpooling, use of high occupancy vehicle lanes, increased use of mass transit, and employee trip reduction programs that may require employers of more than 100 persons to reduce use of cars by their employees.

HIGHLIGHTS

Highlights in the TRIP report include:

Technological strategies to reduce emissions such as cleaner engines and fuels are less expensive to improve air quality ($2,200 and $3,100/ton of emission reduction, respectively) than behavioral strategies such as mass transit improvements and employee trip reduction programs ($272,000 and $281,000/ton, respectively).
A joint EPA-U.S. Department of Transportation study found that behavioral strategies aimed at reducing highway travel will yield only a 1-2% reduction in highway travel vehicle emissions.
Replacing high polluting older vehicles is one of the most cost effective strategies ($3,000/ton of emission reduction). About 50% of motor vehicle emissions are from these 10% of vehicles.
While emissions from cars and trucks decreased between 1984 and 1993, emissions from nonhighway sources increased, offsetting some of the air quality improvements achieved by cleaner highway travel.

Wilkins said, "This clearly shows that some of the strategies now being used to clean our nations' air are extremely costly, not very effective, and may need to be reevaluated."