Atlanta Gunning for Pollution Answers : Environment: Study will gauge the increase in emissions during acceleration and how it can be counteracted.

The city’s drivers are under the gun--a speed gun that is--but they don’t have to worry about getting tickets. Instead, scientists are tracking their driving habits to see if they defeat clean air regulations.

Cars emit about 100 times more pollution during acceleration than they do at steady speeds, but the government has never tested the effect of everyday acceleration on the atmosphere.

“If only a couple of cars are doing that for five seconds at a time and there are 1 million cars on the road, does it make any difference?” asked Michael Meyer, director of transportation research at Georgia Tech.

Tech researchers are aiming laser guns, similar to police radar guns, at hills, highways and intersections to measure how often drivers race their car motors and where they do it.

That information, combined with other data being gathered on the performance of cars, will help researchers learn how often motors are gunned to the point that they spew bursts of pollution, and if emissions laws are strong enough to counter those bursts, said Ted Ripberger, an engineer for the Environmental Protection Agency.

“The models we use to predict emissions don’t take into consideration the way people drive,” Meyer agreed. “This will have impact the next time the Clean Air Act is amended.”

Annual emissions tests are required in Georgia and many other states, but they are conducted while cars idle.

New cars must pass an EPA emissions inspection before they are sold. But the cars are tested only up to 50 m.p.h. and don’t have to accelerate quickly; they only have to reach 30 m.p.h. in six or eight seconds.

Early data from Georgia Tech shows that drivers accelerate twice that fast when they merge with heavy freeway traffic, Ripberger said.

And the average driving speed on Atlanta’s interstates is 62 m.p.h. to 65 m.p.h.--well above the 50 m.p.h. in the test, Meyer said.

Every car has a different acceleration speed at which it reaches enrichment--the few seconds when the engine pumps so much fuel that its emission guards can’t work and it gushes pollution.

Scientists installed computers on 100 cars to pinpoint what types of cars reach enrichment the fastest.

“What we don’t know is how many cars go into enrichment and how often and where,” Ripberger said. “That’s a huge amount of pollution in an instant.

“But if it happens a very, very few times--say only once every 10 minutes per 100 cars--maybe that’s not important.”

If the study shows enrichment is a big problem, scientists must decide if pollution laws or emission tests need to be strengthened. Or they could recommend teaching drivers to avoid quick starts and telling transportation departments to level steep grades.

The EPA picked Atlanta for the $8-million study because it wanted to see how engine bursts will affect air quality during the 1996 Summer Olympics, when traffic will increase exponentially.