Agreement by House-Senate conferees yesterday on how much to weaken auto emmission standards virtually gurantees that a clean air bill will be pass in time to avoid the shut-down the auto industry had threated if Congress left for its August recess without extending current emission standards.

Under the agreement reached by the House and Senate, current emission standards will be extended to the 1978 to 1979 models. But Senate conferees, fighting for the environmentally tougher bill the Senate had passed, succeeded in limiting the length of time the current standards would be extended and the amount the tougher future standards would be weakened after the 1979 model year.

Both the House and the Senate are expected to pass the conference version of the bill by today or Friday, sending it to President Carter for his signature by the weekend.

Auto makers had threatened to shut down production of their 1978 model cars, scheduled to begin Aug. 15, because without the extension tougher air standards would go into effect and the auto makers contended their 1978 cars couldn't meet those standards.

Until the extension is signed into law, the industry would be in violation of Enviornment Protection Agency regulations prohibiting interstate shipment of vehicles not meeting federal emission standards.

Until the extension is signed into law, the industry would be vilation of Environmental Protection Agency regulations prohibiting interstate shipment of vehicles not meeting federal emission standards.

A settlement was reached about 2 a.m. yesterday after seven hours of intensive bargaining by the House and Senate conferees.

Sen. Edmund S. Muskie (D-Maine), conference chairman called the agreement a "reasonable compromise." Rep. Paul G. Rogers (D-Fla.), who headed a House subcommittee that set standards tougher than the House passed, said progress towards cleaning up air pollution from cars was "not as much as it could or should be," but "we are making a little progress."

But Rep. John D. Dingell (D-Mich.), whose district encompasses most of Detroit's auto companies and who fought hardest for the weaker standards backed by the auto industry and United Auto Workers, refused to sign the conference report.

It was Dingell's argument that carbon monoxide exhaust is not harmful to health that caused an apparent breaking point in the hitherto deadlocked conference.

Dingell's statement angered freshman Sen. Wendell Anderson (D-Minn.) who responded with an emotional speech questioning how a person could walk out in the heavily polluted air of Washington this summer and say his health was not affected.

"Driving in from Virginia, I can't see the Washington Monument," Anderson said, adding that air pollution here gave him a "feeling of nausea . . .my eyes hurt."

"There is a health problem. I don't see how a responsible parent could bring children from Minnesota to Washington, D.C.," Anderson said.

Auto emission standards cover three pollutants, hydrocarbons, carbon monoxide and nitrous oxides.

Standards currently in effect allow 1.5 grams per mile of hydrocarbons, 15 grams per mile of carbon monoxide and 2 grams per mile of nitrous oxides. These would remain in effect through the 1979 model year, under the bill.

Then for the 1980 model year the hydrocarbon standard would be tightened to .41 gram per mile and carbon monoxide standard to 7 grams per mile; the nitrogen oxide standard would remain the same.

For the 1981 model year, hydrocarbon standard would not change, but the carbon monoxide standard would drop again to 3.4 grams per mile, and the nitrogen oxide standard to 1 gram per mile.

However, the 1981 carbon monoxide and nitrogen oxide standards could be waived for two more years under certain conditions.

In addition to dealing with air pollution from automobiles, the bill sets up a classification system for how much dirtier areas - primarily in the West - that are no clean could become.