Environmental Protection Agency Administrator Anne M. Gorsuch want American business to "light up the switchboards" boosting the administration's Clean Air Act package in Congress, where mail is running against the legislation.

Nearly 300 Washington corporation representatives and trade association executives, including many with a large stake in air pollution rules, crowded the Chamber of Commerce's Hall of Flags here last week in response to an invitation from chamber legislative vice president Hilton Davis.

According to some of those present, Gorsuch outlined the general principles the administration wants to incorporate in loosening the Clean Air Act when the rewriting begins in earnest in September.

President Reagan's budget and tax packages were two legs of a three-legged stool, she said, and the Clean Air Act is symbolic of the third leg, regulatory reform.

"Let's light up the switchboards for this with the same intensity as we did on the other two," she said to the business executives. "We have observed what this can accomplish."

Gorsuch also said in response to questions that she did not plan to revamp air pollution regulations before Congress deals with the act. "We don't want to confuse the issues," she said.

That runs counter to sentiment within the Office of Management and Budget favoring administrative action to loosen air pollution restrictions while Congress is debating.

The business community had responded to Davis' letter that said business support for the administration is "increasingly critical in view of the heavy flow of mail against amending the act already being generated by environmental organizations.

"One source said the mail is running 200 to 1 against the [administration] amendments," the letter continued.

That figure came as a surprise to David Hawkins, who ran EPA's air program in the Carter administration and now is with the National Clean Air Coalition of environmental groups. "It's not a product of our activities at this point, but it comfirms that we've been saying all along," he said.

He added, that it is "outrageous that the head of EPA should be stirring up the regulated industries to counteract popular support for clean air."

Devis said Gorsuch got "a very warm reception" for her 25-minute appearance and that it had resulted from a standing offer he had made to provide a forum for her whenever she was ready to talk about the Clean Air Act.