The Environmental Protection Agency, in one of the most controversial and expensive regulations ever adopted, told the utility industry yesterday to cut allowable air pollution from new coal-fired power plants in half.

However, the new rules will not reduce overall sulfur emissions in the near future because existing plants are not affected and coal use is expected to almost triple by 1995. New plants will be cleaner, but there will be more of them.

The standard, which is a relaxation of a stricter rule proposed in September, came after one of the most intense regulatory battles of the Carter administration. EPA was under extreme pressure by the coal and utility industries, the White House, the Energy Department and a coalition of senators from coal-producting states led by Majority Leader Robert Byrd (D.-W.Va.).

However, EPA Administrator Douglas Costle yesterday dismissed the pressure as "a tempest in a teapot." He said, "It's gotten to be a symbolic issue . . . On balance we've come out with a very tight standard."

The new rules retain the current emissions ceiling of 1.2 pounds of sulfur per million BTUs but require plants to remove between 70 and 90 percent of the sulfur from their emissions. EPA had proposed earlier an across-the-board scrubbing of 90 percent and was considering an emissions ceiling as low as 0.55 pounds. Because of the scrubbing requirement in the new rules, sulfur emissions from many new plants will be well below the 1.2-pound ceiling.

Environmentalists attacked the final standard as a weak compromise resulting from political pressure. "In the 40 years that these plants operate, the people of the United States will suffer from unneccessary disease, reduced agricultural and forest productivity, and further degraded visibility," said Richard Ayres of the Natural Resources Defense Council.

"In the West, it means that more and more of our most priceless scenic assets, such as the Grand Canyon, will be visible only through the dismal haze of smoke."

The League of Women Voters expressed "disappointment that the administration decided not to vigorously push forward with its commitment to full environmental protection."

However, coal industry executives said they were pleased with the outcome. "America has won a big victory," said Carl E. Bagge, head of the National Coal Association. "The standard represents an honest attempt to balance future national environmental and energy objectives."

George Freeman, a utility industry lawyer, said of the new standard, "I'm pleased in some ways and disappointed in others. I'm glad they retained the 1.2-pound ceiling but cost effectiveness went out of the window with the 70 to 90 percent scrubbing." Utilities, backed by Energy Secretary James Schlesinger, had pushed for a 33 to 85 percent rule.

By retaining the 1.2-pound ceiling and requiring at least 70 percent scrubbing of even low-sulfur coal, EPA is tilting the balance of coal production away from the West's massive low-sulfur reserves toward eastern and midwestern high-sulfur coal, a move ordered by the 1977 Clean Air Act amendments.

Earlier air pollution laws had allowed eastern utilities to avoid building expensive scrubbers by shipping massive amounts of low-sulfur coal from the West. The shift toward western coal led to massive stripmining in the West, as well a loss of jobs in eastern coal mines.

Now that western coal must be scrubbed regardless of sulfur content, and a strict emissions ceiling allows the burning of even the dirtiest eastern coal, the economics incentive to ship western coal is reduced. Costle estimated 30 percent less Western coal would be shipped East by 1995 as a result of the standard. However, production will still increase considerably in the West because of local demand.

The new standards will cost utilities $35 billion by 1995, or $3.3 billion a year in annualized costs, including financing expenses-an amount equal to 2 percent of the cost of building the plants. The average citizen's electric bill would rise by $1.20 a month, EPA said.

The Natural Resource Defense Council and the Environmental Defense Fund said yesterday they are considering a joint suit contending that the law requires 95 percent scrubbing, and that the EPA backed down because of political pressure outside legal rulemaking procedures.

They cite meetings in which Energy Department and Council of Economic Advisers officials lobbied EPA after the close of the public comment period.Also, Sen. Byrd and about 20 senators personally met with President Carter in an effort to prevent EPA from tightening the emissions ceiling.

On the other hand, Interior Secretary Cecil D. Andrus, Sen. Edmund S. Muskie (D-Maine) and the chairmen of several House environmental subcommittees urged Costle not to relax the proposed standard.

Byrd praised EPA yesterday for adopting a "flexible" standard. "I am pleased that a coalition of coal state senators, coal industry represntatives and union officials were able to provide sound arguments that were useful in EPA's reaching a decision," he said.

The power plant standard is among the most important environmental decisions the administration will make. In 1976, power plants accounted for 65 percent of the nation's sulfur emissions (which can irritate the upper respiratory tract and cause lung damage), 24 percent of particulates (which can cause breathing problems and respiratory illness) and 24 percent of nitrogen oxies (which can cause bronchitis and pneumonia).

The power plant emissions also are causing grave problem through sulfurloaded "acid rain," which has killed fish in 300 lakes in northern New York and is rapidly spreading through Canada.

Costle said the nation must discover new energy sources to replace coal within 25 years because of another coal-burning pollutant, carbon dioxide, which threatens to drastically alter the world's climate.