The House last night passed by voice vote a clean air bill extending current auto emission standards, but the bill faced the threat of a filibuster in the Senate.

Sen. Jake Garn (R-Utah) threatened to filibuster the bill because many clean air areas in the West would not be allowed a variance permitting an additional amount of pollution for a certain number of days. Garn says the restriction would limit growth in his many other Western states by preventing the building of additional power plants.

However, sources said Majority Leader Robert C. Byrd (D-W.Va.) was determined to push the bill through, even if it meant keeping the Senate in session beyond the Saturday target it had set for adjournment for a month-long vacation.

Garn, with the backing of utility lobbies, successfully filibustered the clean air bill to death in the cosing days of the 1976 Congress. But then he was joined by the auto obby, which chose to allow the bill to die rather than accept the agreement on auto emissions which it consedered too stringent.

This year, the auto industry desperately wants a bill and even threatened to shut down production of 1978 model cars, scheduled to begin Aug. 15, unless a bill passed.

Without the bill, which extends the current auto emission standards for two model years, 1978 and 1979, stringent new auto emission standards are scheduled to take effect which Detroit says the 1978 models cannot meet. The auto industry would then be in violation of environmental Protection Agency regulations, which prohibit cars that do not meet the standards from being legally shipped across state lines.

The bill agreed upon by House and Senate conferees, did not weaken auto emission standards as much as the auto industry wanted, and was consider a victory for Sen. Edmund Muskie (D-Maine), Rep. Paul Rogers (D-Fla.) and environmentalists.

The auto industry favored a weaker bill passed by the House, which had accepted a longer delay and weaker cardon monoxide and nitrogen oxide standards than did the Senate.

The 1977 auto emission standards, retained for the 1978 and 1979 model years, cover the three auto pollutants - hydrocardons, carbon monoxide and nitrogen oxides. Current standards allow 1.5 grams per mile for hydrocarbons, 15 grams per mile for carbon monoxide and 2 grams per mile for nitrogen oxide. In model year 1980, the standards would dip to .41 grams per miles for hydrocarbons, 7 grams per mile for carbon monoxide and 2 grams per mile for nitrogen oxide. Hydrogen standards would remain the same for model year 1971, but carbon monoxide would go to 3.4 grams per mile and nitrogen oxides would go to 1 gram per mile with a two-year waiver possible on both under sertain conditions.

Warranties for emission-control devices would be reduced from five years and/or 50,000 miles to two years and/or 24,000 miles.

The bill also for changes in the clean air standards for plants and factories and other nonmobile sources.

Areas, primarily in the West, which are now cleaner than the standards permit would be out in to three classes. Class I, which would include large national parks and wilderness areas, would have to remain pristine. Class II would allow a certain percentage of degredation in air quality and Class III a larger percentage of air deterioration.

Most areas would be designated Class II, but the states could, with certain restrictions, redesignate into one of the other classes.

The House adopted a provision for Class I and Class II areas that would permit a governor to allow dirtier air up to 18 days a year. In the conference however, only Class I areas were permitted this variance. It was to allow variance for Class II areas that Garn threatened to filibuster.

The bill also put new pollutants under regulation, including airborne radiation, which means that the EPA would regulate for the first time pollutants from nuclear power plants, which are now regulated by the Federal Energy Administration and the Energy Research and Development Agency.

The bill would allow 5 to 10 more years to states that do not meet present clean air standards (largerly big-city areas) to meet those standards and to take in new industry - providing "reasonable progress" toward the standards was being made.