State officials and environmentalists said the ruling would help New York meet smog standards.

But the book doesn't mention that an area fails the smog standard if even one of its air quality monitors shows an excess pollutant for four hours per year.

The court also said that in setting smog standards, the E.P.A. had exceeded its powers.

Under the Clean Air Act, the ozone commission is allowed to ask Washington for rules that would help the member states meet smog standards.

"There have been serious breaches of the smog standards," said Pat Macken, a spokesman for the Department of the Environment.

Mr. Chafee would maintain smog standards at the current level of stringency while changing somewhat how violations are measured.

Lawsuit-proof cuts of nitrogen and sulfur are needed to end acid rain damage and let downwind Eastern states meet stricter smog standards.

According to E.P.A. data, the New York City region violated federal smog standards on 69 days in 1980.

The regulators acted at the request of New York, Connecticut, Massachusetts and Pennsylvania, which said they needed help to meet national smog standards.

Nationally since May 1, there have been only 14 days when the smog standard was not exceeded somewhere, she said.