In this country, mess with our cars and you're hitting us where we live -- even if it's in the good cause of cleaning up America's polluted air.

A few years ago the District of Columbia tried testing automobile exhausts when people brought their cars in for regular annual inspections. It was a pollution-study experiment. Nobody had to comply.

People went crazy. They were so upset, said the city's manager of vehicle inspections, Bob Kozak, that 20 percent refused to let inspectors near their tailpipes.

Now the news: Emissions testing is coming soon for every car and light truck in the Washington area. Projections are that 350,000 vehicles will flunk the first time around -- one out of every five. Owners will have to pay up to hundreds of dollars each for repairs.

All this is required here and in 37 other metropolitan areas around the country under the Clean Air Act, the sweeping environmental legislation that prompted a multibillion-dollar, decade-long cleanup of the nation's air.

The cleanup sharply reduced pollution from America's cars and light trucks: hydrocarbon emissions went down 35 percent, nitrogen oxides 12 percent and carbon monoxide 43 percent in a decade. Emissions should continue to decline through the 1980s until most vehicles on the road will have been manufactured after 1981, when the most sophisticated pollution control equipment is being installed.

Despite the improvement, automobile-caused smog remains the biggest pollution problem in the Washington area, much of the northeast and California. To make further progress against it, the act requires emissions inspections in these areas. The smog is mostly a gas called ozone, which is produced when sunlight strikes hydrocarbons and nitrogen oxides in the air.

"There's no question Washington's problem is the auto," said Hank Sololowski, an EPA official.

Today, America's clean air saga has reached a critical juncture as industrialists and Reagan administration economists attack it as inflationary. The administration has targeted the Clean Air Act in its regulatory reform effort, and already has curbed many vehicle emissions rules in an effort to aid the financially tottering auto industry.

Congress is in the midst of an enormous debate over the act this year. For issues in the Capitol Hill battle will produce as many sparks as the question of how far to go in regulating the emissions of our cherished chariots.

Many believe we already have gone too far and that Congress has no business ordering states for force emissions inspections on their citizens.

"Absurd," Virginia Del. Larry Pratt (R-Fairfax) said of the measure. He said air quality is getting better without it and this is "not the time to spend more money on it."

The Virginia and Maryland legislatures resisted inspections but gave in when the U.S. Environmental Protection Agency threatened to strip them of federal highway and sewer funds -- a penalty provided for in the act.

Virginia De. Mary A. Marshall (D-Arl.) helped push the measure through the legislature but said it passed only because the state would have lost $350 million in federal funds by rejecting it. She called it "a really rotten law" that "will do nothing for motorists and will cause harrassment."

Nationally, inspections pose a "monumental political problem," said Walter C. Barber Jr., the EPA's deputy assistant administrator for air quality planning and standards. "I've never met anybody who wants to take their car and get it inspected and have to fix it if it doesn't work right."

Officials like Kozak charged with implementing the programs say typical repair bills should be modest and people should not get upset.

We're not going to take the car away from the little old lady in tennis shoes," said Ray J. Salehar of the Maryland Motor Vehicle Administration.

Said Kozak: "We're just saying, 'Look, keep it in a reasonable state of tune."

Nevertheless, it appears the Reagan administration may try to kill the regulations, making the programs optional.

In Maryland recently, state transportation official Frederick Dewberry told the House of Delegates appropriations committee that if this happens Maryland might be saddled with a $20 million bill for a program it did not have to implement and did not want in the first place.

"It's not material what the federal government does," replied committee Chairman Torrey C. Brown (D-Balt.) He said the benefits of clean air are worth the cost.

That opinion is the subject of a raging national debate.

Detroit says pollution control equipment adds nearly $500 to the sticker price of your car, although the EPA estimates it is more like half that. General Motors says meeting the federal standard for smog is going to cost consumers billions.

On April 6, the Reagan administration relaxed 34 environmental and safety regulations that it said represented regulatory overkill. The action aimed at putting 200,000 auto workers back on the job and is supposed to save consumers $9.3 billion in five years. Vice President Bush said the changes will not harm the environment.

Nonsense, said critics. "In effect, they have repealed the motor vehicle safety and emission laws," said Ralph Nader. "They are going to do nothing, period, zero, for four years."

Richard Ayres of the National Resources Defense Council charged that the administration is "giving the auto industry the regulatory advantages it has sought for a long time, which have little if anything to do with its financial problems."

The arguments do not divide neatly along partisan lines. Paul R. Portney, who was an environmental adviser to President Carter and who now is a senior fellow at Resources for the Future, an independent Washington think tank, said America is "grossly overcontrolling" automobile pollution.

"Although I'm a Democrat and was part of the Carter White House, I'm not alarmed at the close scrutiny the Reagan administration is giving the regulatory process" where it concerns the Clean Air Act, he said.

Portney bases his opinion on studies showing that ozone, the main component of automobile-caused smog, does not cause serious health effects or higher mortality. Other pollutants like sulfur oxides and particles from factories and power plants do, but these have been largely brought under control.

"We spent $8 billion a year on controlling automobile pollution," Portney said. "They may be twice as much as the benefits we get."

His suggested solution is to clamp down on auto emissions in 10 to 20 big metropolitan areas but "not make the poor guy in Podunk pay the extra $500."

A similar conclusion was reached by the National Commission on Air Quality, a bipartisan group that issued an official report on the Clean Air Act in preparation for the congressional debate. It recommended inspections be required only in urban areas of over 500,000 population where air pollution levels exceed federal standards by more than 50 percent.

The Washington area might qualify for examption under such a relaxed rule. The area's 1982 carbon monoxide levels are projected at 35 percent over the standard, and the worst ozone levels here in recent years have been about 50 percent over the standard.

It took strong measures to cut automobile poolution during that last decade. In the 1970 Clean Air Act Congress ordered automakers to reduce emissions 90 percent by 1975 or face fines of $10,000 per car per day. The deadlines were relaxed, but Detroit got the message and met standards that became progressively stringent through the 1970s.

The early pollution control equipment was cumbersome and limited in its impact. After 1975, however, vehicles were equipped with effective catalytic converters. Most cars made in 1981 and later will have sophisticated computer-regulated emmissions control systems.

The emissions inspection programs are needed to capture the gains made by detroit's "technological fix," because once cars roll off the assembly line onto the road there is a spectacularly quick increase in their emissions.

So quick, in fact, that the commission found the average emissions of all model years of automobiles on the road to be in excess of federal standards, with some limited exceptions.

For example, 1980 model cars emit an average of 1.74 grams of hydrocarbons per mile, which is much better than the 8.15 grams per mile emitted by 1967 cars but still four times the standard of .41 grams.

In a New Jersey inspections program, officials found that 9 percent of 1973 model cars failed when tested that same year. The next year, the failure rate for the 1973 models jumped to 15 percent.

This finding is all the more remarkable because when cars come off the assembly line their average emissions are significantly below standards, even though 230 percent fail to meet one or more.

If you happen to own one of the cars among this defective 20 percent, the act protects you. Under it, manufacturers must repair free a vehicle that fails an emmissions test if it has been prooperly maintained.

Officials here say this means consumers and manufactures will haggle over what constitutes proper maintenance. A further burden is placed on consumers because the act does not allow states to inspect cares before dealers deliver then to customers -- a concession to Detroit that Kozak called infuriating.

Acording to the commission, failures of "in-use vehicles" to meet emissions standards results not only from deteriorating equipment but also from improper maintenance, tampering, fuel switching, and operation at high altitude.

Officials say emissions inspection programs do not seek to make every car on the road conform to the tough federal standards. That would mean "flunking over 50 percent of the cars on the road," Kozak said, "Poltically, that wouldn't be too much fun."

Instead, local officials will try to find cases where big improvements can be made with relatively cheap tuneups and carburetor adjustments.

"It's not going to be a draconian measure," Kozak said. "We're looking to hit those cars that are in bad shape, people who don't keep their cars in tune and are losing gas mileage, anyway." He said he wants to find people who tampered with their equipment or destroyed their catalytic converters by using leaded gasoline.

Repairs in these cases could run to hundreds of dollars, but most people would not face bills like that. In an Oregon inspection program, less than 10 percent of cars failing cost more than $50 to repair and more than 70 percent cost less than $10.

In addition, the EPA says that repair costs may be balanced by fuel savings. A California study, for example, showed that people had to pay an average of $15.41 to meet the emissions standards, but the repairs brought a $15.83 fuel saying by making engines run more efficiently.

The EPA says 19 percent of America's automobile fleet since 1972 has been tampered with -- a phrase that in the bureaucratic mind covers improper maintenance, engine misadjustment and fuel misuse whether purposeful or accidental.

Officials say they expect about 20 percent of the 1.8 million vehicles in the Washington areas to flunk the tests the first time around. Tests begin next January in Virginia and the following January in Maryland and the District of columbia.

Inspection programs already implemented in several cities have been successful. In Portland, the EPA found inspections reduced hydrocarbon emissions 24 percent and carbon monoxide 34 percent. Similar reductions were found in California programs.

Nationally, the EPA estimates that if all cars and light trucks are inspected, hydrocarbon emissions will drop 23 percent and carbon monoxide 26 percent by 1987.

While emissions inspections are considered importants, the act lists other measures states may implement to curb auto pollution -- improved public transit, private car restrictions, street parking controls, more bike lanes and pedestrian malls, and road-pricing to discourage single-occupancy automobile trips, among others.

In Washington, the Metropolitan Washington Council of Governments, an association of local governments, is developing plans to implement some of these so the area can meet federal air standards. COG will assess the economic and social impact of various measures, and there will be public hearing before local jurisdictions implement any.

Most of the measures -- like the official encouragement of van pooling -- have little impact compared with gains from emissions inspections, and they often are controversial because they aim to keep people out of their cars. t

Federal employes screamed when the Carter administration tried to make them pay for parking spaces in an effort to save fuel and curb emissions. A judge killed the plan, but it may yet be implementad under the requirements of the Clean Air Act.

"The auto is a sacred item. You can't touch it," said Edward O. Jess of the Virginia Air Pollution Control Board. He said officials encourage people not to drive during polluted periods but "so far we're gotten no tremendous amount of help from them."

COG transportation specialist Phillip S. Shapiro said tough measures like tolls on the Virginia bridges could be avoided if officials treated pollution alerts as temporary emergencies like snowstorms. Under this plan, people would be ordered not to drive on the few days each summer when pollution is worst.

For technologist reasons, too, there are limits to cutting emissions by taking people out of their cars.

A study quoted by Shapiro shows most hydrocarbon emissions come from cold starts and "hot soaks" after the ignition is off. So if you drive two miles, park and take the subway another eight to work, your car will still emit 60 percent what it would have had you driven all the way.

In a study with other transportation planners, Shapiro wrote that eliminating all work trips in the entire Washington area would decrease automobile hydrocarbon emissions only 12 percent.

Americans have always sensed that emissions equipment cut into mileage, and the EPA recognizes this by waiving certain standards if it will result in fuel savings.

However, the equipment now is so sophisticated that the tradeoff may no longer be so severe. "Contrary to popular belief, auto fuel economy and clean air standards are not at odds," says the Manufacturers of Emission Controls Association.

An association news release says each time emissions standards were tightened "the auto industry responded with better fuel economy over and above gains due to weight reduction."

Cars with diesel engines will not be inspected in the new programs, but EPA officials are concerned about them because they may accounted for 25 percent of car and light truck sales by 1995 and they emit more nitrogen oxides and 30 to 100 times more soot than gasoline vehicles.

In February 1980 the EPA tightened standards for diesel soot from cars and light trucks. Then-EPA chief Douglas Costle said this would add $165 to sticker prices for these vehicles, but that the action was necessary because the soot is linked to emphysema, brochitis and asthma.

Another automobile-caused air pollutant, lead is a problem here and in most of the nation's major metropolitan areas, but the commission report said that the increasing use of leadfree gasoline soon will solve it in all but a few California cities.

As things stand now, jurisdictions here are going ahead with emissions inspections programs. Maryland's Salehar said he thinks the state will go ahead with its program even if Congress or the administration makes it optional.

"They might modify the program but they'll keep it because it's the last hope they've got of cleaning up the air," Salehar said.

Marshall, the Virginia politician, said she did not think that would be the case in her state.

"It just downed on me slowly what a bad piece of legislation I put through, " she said. "It was worth it to save $350 million, but if I can get rid of it now, I'll feel I've done my duty to the commonwealth."