The number of U.S. cities with excessive ozone pollution dropped to 62 in 1984-86, but the cities still on the list included such metropolises as Los Angeles that have no chance of meeting federal standards by the end of the year, the Environmental Protection Agency said yesterday.

"If you took every car off the streets of Los Angeles, they still couldn't meet it," said agency spokesman Chris Rice. "There's a 70 percent reduction needed {in ozone pollution}. Taking the cars off would only be a 50 or 55 percent reduction."

The EPA also said 65 cities violated the limits on carbon monoxide during 1984-86.

Baltimore ranked 23rd and the Washington metropolitan area was listed 40th on the EPA's ranking of 62 cities with too much ozone pollution. On the carbon monoxide list of 65 violators, Baltimore ranked 15th and the District 58th.

The overall figures reflect an improvement over the EPA's previous report, covering the years 1983-85, when 76 cities violated the ozone standard and 81 violated the carbon monoxide standard, Rice said.

He said the EPA's "emphasis is normally much more on ozone. We believe the carbon monoxide problem is only a long-term problem for a few cities."

The Clean Air Act requires that all areas of the country reach the standards by Dec. 31, and the EPA will use data from 1985-87 in judging which have complied, Rice said.

Ozone is a form of oxygen produced by reactions in sunlight between nitrogen oxides, the combustion of fossil fuels and chemicals such as unburned gasoline and certain solvents. A layer of ozone 15 miles to 25 miles high protects Earth from harmful ultraviolet rays, but ground-level ozone is a key element in smog.