Smoke-filled rooms may be a tradition on Capitol Hill, but smoke from the Capitol Power Plant violates the Clean Air Act, a public interest law firm complained yesterday.

With the audacity of a militant nonsmoker telling the boss to put out his cigar, the Capital Legal Foundation served notice on Congress that it will go to court if necessary to try to shut down the polluting power plant.

The offending smokestacks not only provide heating and cooling for the legislators who wrote the Clean Air Act but also for the Supreme Court justices who ultimately could decide the case.

Congress usually exempts itself from laws governing ordinary citizens but, when the lawmakers passed the landmark pollution legislation in 1970, they included federal facilities. "The federal government cannot expect private industry to abate pollution if the federal government continues to pollute at will," a Senate committee proclaimed.

Seeking to hold Congress to its word, the private, industry-backed legal foundation invoked yesterday provision of the law that allows any citizen affected by pollution to sue the polluter.

Emissions from Congress' power plant do not meet standards set by the District of Columbia clean air plan, the foundation complained. As recently as last December the plant, at South Capitol and E streets SE, was cited for violation District standards on eight occasions.

As required by law, the foundation gave Congress 60 days notice that it intends to file a Clean Air Act law- suit. If the pollution is not stopped by then, the polluter could face a fine of up to $25,000 a day or shutdown of the plant.

Notice was sent to the Capitol Power Plant Commission, whose chairman is House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), and to George White, Capitol architect.

White, who is in charge of keeping Congress' house in order, insisted that the plant is not fouling the air. "So far as I know, we're in compliance" with District pollution limits, he said.

White said the plant has installed expensive antipollution gear and hired costly consultants to control its emissions. "I would be astonished to find that we were not in compliance," he said.

If White sounds like some frustrated businessman complaining about the federal bureaucracy, it's no accident. "We're practicing some symbolism here," admitted James R. Richards, legal director of the foundation.

Richards said the foundation obtained District air pollution reports under the Freedom of Information Act and that they show violations by the congressional plant. When D.C. inspectors attempted to serve a violation notice on the plant in January 1978, the officials at the plant refused to accept it, the documents show.

Responding to complaints from District inspectors who saw smoke being emitted by the plant on eight occasions last December, plant engineers said smoking was unavoidable during certain phases of the operation.

When crews pull ashes from the burners or switch boilers, the plant puts out smoke, said John H. Berlin, chief engineer at the plant.

To end complaints about smoke spewing from the stacks, Berlin assured city officials that "we have given the watch foreman instructions not to pull ashes or transfer loads on boilers during the daylight hours."

Richards said a private power plant that tried to hide pollution by puffing it out at night would face heavy penalties from the Environmental Protection Agency.

The capital Legal Foundation earlier sued the government to try to stop pollution from two General Services Administration power plants that serve other federal buildings. That case is pending.