The latest version of the Clean Air Act may require Utah service stations to improve the recovery of gasoline vapor at the pump - but most of the changes it imposes will be made at the national level, according to Environmental Protection Agency experts.

Shortly before Congress adjourned for the elections, it passed a complete revamping of the Clean Air Act, the environmental legislation that has guided efforts to protect the atmosphere since 1970.National changes are in areas such as forcing auto manufacturers to meet stricter emissions standards. Still, some of the act's hard-fought compromises will be reflected in differences in the way Utahns do business.

Salt Lake and Davis counties will have to control sources of ozone emissions more strictly, said Jeff Houk, environmental engineer with the EPA in Denver.

Ozone pollution must be reduced by 15 percent within six years in Salt Lake and Davis counties, and the auto inspection and maintenance program should be extended Weber County, he said.

This is because Weber County is part of the Salt Lake-Ogden Metropolitan Statistical Area, he said.

The state will also have to submit a "stage II" gasoline vapor recovery plan.

"In the past, we've set targets for states to attain the federal air quality standard," he said in an interview Monday. "We've allowed the state to develop a plan to meet that deadline, without meeting interim milestones."

But under the act's revisions, the state will be forced to meet deadlines for ozone reductions. The EPA calls these reduced levels "milestones."

"They have to submit a revised plan within two years, and those milestones occur yearly. Each year they have to show that they've achieved a certain amount of emissions reductions compared to the year before."

Vapor recovery can be achieved by special devices fitted to the nozzles of gasoline hoses.

Another area where Utah would have been required to take action - if it had not already - is in carbon monoxide control.

The auto inspection and emission program in place for Salt Lake, Davis and Utah counties presently uses manual inspection analyzers. In the garage, when the mechanic checks for air quality compliance, he uses devices that fit into the car's tailpipe and checks for carbon monoxide and hydrocarbon pollution.

The revisions will require the use of "automated test analyzers" tied in to computers. The devices will take away the discretion of the technician, leaving the pass-fail decision up to the computer.

Changes on the national level that will help Utahns breathe more freely include: Rules that force light trucks to meet high-altitude standards, reducing emissions in lofty places like Salt Lake City and Denver.

- A clean fuel program for urban buses.

- Reduced emissions from cars during operation and refueling.

- Plans to reduce fine-particle pollution must include controls on wood-burning and urban dust for areas moderately beyond the standard, like Salt Lake City and Magna.

- Requirements that toxic air pollutants be reduced over the next 15 years, and that power plants cut down sulfur dioxide and nitrogen oxide emissions by the year 2000 in order to reduce acid precipitation.

- Charging industry at least $25 per ton of pollution released. The more an industry emits, the higher the cost for its permit.