The Environmental Protection Agency has announced tighter controls on car and truck exhausts, forcing automakers to build cleaner vehicles beginning in 1994.

EPA said Tuesday that the rules, required by last year's Clean Air Act, should help reduce smog in the nation's cities. They will be the first tightening of exhaust pollution standards since 1981.The agency estimated the cost of meeting the new controls at about $152 per car and between $57 and $157 per truck, depending on its weight.

"Auto manufacturers have made tremendous progress reducing vehicle emissions - 80 percent since 1970," said EPA Administrator William K. Reilly. "Yet, during the same period the number of vehicles on the road has risen sharply, making it hard to achieve overall air quality."

About 118 cities exceed federal carbon monoxide and ozone air quality standards, the agency said.

The new standards will be phased in over three years.

"The manufacturers will have difficulty meeting them, yet the technology to meet them does exist," said Marcel Halberstadt, director of the environment department for the Motor Vehicle Manufacturers Association.