With angry motorists lighting up legislators' switchboards and sounding off on radio talk shows, Maryland's new emissions tests don't have many fans these days.
Citizens are indignant about the expense, inconvenience and intrusiveness of the tests, which cost more, take longer and are tougher than the checks done by the state for the past 10 years.
"Enough is enough," said Robert Cadwalader, a commercial pilot from Linthicum who's worried about strangers handling his minivan. "The quest for 'pure air' is going too far."
What price clean air? Is it worth having a stranger "drive" your car on a treadmill-like device at speeds up to 55 mph? What about the estimated 1-in-5 chance of failing the test -- and then having to get a tune-up or repairs to the emissions controls?
"I can't tell you how outraged people are," said Del. Martha Klima, a Republican from Baltimore County. She has drafted a bill to repeal the 1991 law that authorized the testing scheduled to begin Tuesday.
"I think we all want clean air, but there's got to be a balance between the rights of citizens and the mandates of government," she said.
Auto emissions testing is about as enjoyable as going to the dentist, said David A. C. Carroll, Maryland's environment secretary. But he said it's necessary if Marylanders want to clean up the smog that hangs over the Baltimore-Washington region every summer.
Though progress has been made against smog, it still affects the health of hundreds of thousands of Marylanders, state officials say. Cars, minivans, sport-utility vehicles and light trucks are a leading source of the pollution, and nothing else can reduce it as much as the emissions testing.
Checking nearly 2.5 million vehicles every other year, and requiring repairs on autos that fail the tests, will remove more smog-forming pollution from Maryland's air than if every factory in the state shut down tomorrow, Mr. Carroll said.
The controversy over vehicle inspections is not unique to Maryland. In deciding to get serious about fighting urban smog, Congress ordered tougher vehicle emissions checks for some 80 metropolitan areas in 22 states and the District of Columbia.
As one of the first states to upgrade its emissions inspections, Maryland is on the leading edge of a nationwide tempest over the federal requirements to combat smog that Congress wrote into the Clean Air Act in 1990.
Maine was actually the first to begin the "high-tech" inspections last summer. But it suspended testing soon afterward amid motorists' complaints and allegations that the state was squeezing motorists while favoring industrial polluters such as paper manufacturers.
Advanced auto inspections are to begin early this year in threother states: Arizona, Colorado and Texas. Maine also plans to resume testing.
Yet other states, including Delaware, Pennsylvania and Virginia, have rebelled against federal pressure to set up state-run testing stations. Auto repair shops in those states object to an Environmental Protection Agency requirement that testing be done independently of where the vehicles might get fixed.
After initially threatening to withhold federal highway funds from recalcitrant states, EPA officials have backed off, offering the states more time and "flexibility" to develop alternative testing plans.
In Maryland, some critics of the new testing program want to stick with the old one. Other critics say the state should find less onerous ways to control pollution.
But Maryland officials say there is no turning back, because of the extent of the smog problem in the Mid-Atlantic and Northeast.
States such as Maryland will be hard pressed to eliminate smog, even with every pollution control proposed so far. States looking to give their motorists a break probably will have to compensate by cracking down that much harder on smokestack industries and even small businesses such as dry cleaners or bakeries, which already have been required to curtail emissions.
Auto emissions testing "is one of the most cost-effective strategies we know about," said Richard Wilson, deputy air administrator for EPA.
To be sure, the air has become easier to breathe in Baltimore and over much of the country in the past 25 years, mainly because of federally mandated crackdowns on smokestack pollution and auto emissions. But smog continues to foul the air in Baltimore, Washington and many other metropolitan areas throughout the country.
Up to 4 million Marylanders breathe unhealthful levels of ozone every summer. Most probably do not notice the invisible pollutant, formed when the sun's heat causes hydrocarbons and nitrogen oxides to combine in the air. But it can cause wheezing and shortness of breath in sensitive children and adults if they play or work outside. Doctors say that about 600,000 children and adults with asthma, bronchitis or other chronic breathing problems are especially vulnerable to the gas, which is a lung irritant.