To most people, it is a lawn mower, but to the Environmental Protection Agency it is an "uncontrolled mobile source" of pollution that becomes part of the suburban swarm, adding measurably to smog on a summer's day. And the time has come, the agency says, to clean it up, along with lawn trimmers, leaf blowers, chain saws and a lot of other off-road, gas-powered machinery.
A lawn mower can easily spew as much smog-causing hydrocarbon into the air in an hour as a modern car, experts on pollution say.
Tomorrow, William K. Reilly, the administrator of the Environmental Protection Agency, and an organization of electric utilities plan to announce the start of a program to clean up America's lawn mowers.
Baltimore Gas and Electric and nine other utilities will each give away 100 newly designed battery-powered mowers made by Black & Decker, taking their customers' old gasoline models in trade and asking them to test the new mowers in the field -- or, more precisely, on the lawn -- and report back on their performance.
The new electric mowers being distributed in the test program will be able to mow about a quarter of an acre without recharging. A full charge takes 20 hours; an 80 percent charge 4 hours.
The mower, which will sell for about $500, will use about 6 cents' worth of electricity per charge. The use of electricity is expected to decrease overall pollution.
Meanwhile, the EPA will haul the old mowers into its labs to study their emissions, in preparation for issuing new air-quality regulations similar to the rules now in place for cars and trucks.
The effort on lawn mowers will be part of a plan that will eventually cover all kinds of engines, small and large, used off the highway. That would include construction equipment, farm tractors and even the service vehicles on airport aprons.
In its new get-tough approach, the EPA plans to make an example of the lawn mower. "We joke around and call it the last frontier for mobile sources," said Gay McGregor, an air-pollution specialist in the EPA's mobile-source laboratory in Ann Arbor, Mich.
The lawn-mower-engine industry, after initial resistance, is acknowledging the mighty little machine's role in air pollution.
At the Outdoor Power Equipment Institute, formerly the Lawn Mower Institute, Dennis C. Dix, the executive director, conceded, "We certainly could do better."
His industry, which never worried much about exhaust, is being forced by California to abide by new regulations that are to take effect in 1994 and 1999 and may be extended to other states as well.
Ann McClure, the executive vice president of the Professional Lawn Care Association of America, said: "There's an irony in this. Turf actually helps to cleanse the air, taking what emissions there are in the air, removing them, and replacing them with oxygen."
At Caterpillar Inc. in Peoria, Ill., a big maker of the type of agricultural and heavy construction equipment that is likely to be regulated soon, Rita L. Castle, said that the trend was "not unexpected." She added, "They've gone after most of the large emissions sources, and off-road vehicles certainly deserve a close look."
At the Toro Co., Karl C. Kaukis, the director of marketing for the Lawn Boy line, said lawn mowers could be cleaned up, but consumers would find them more costly. He added that he hoped for "a common sense approach."
Nobody is certain how many lawn mowers are in use or what their emission levels are after a few years without being tuned up, but an EPA study late last year suggested that in areas that are already in violation of smog rules, nearly 20 percent of volatile organic compounds and nearly 30 percent of nitrogen oxides come from "non-road sources." Mixed with sunlight, those two chemicals make smog.
Most manufacturers will try to lower emissions from gasoline engines by redesigning the combustion chambers, in many cases switching to overhead valves instead of side valves, a change made by the auto industry 40 years ago.