Today's lawn mowers and tractors generate more than 70 percent less exhaust emissions than they did in 1995, when California first regulated small-engine emissions. This outdoor power equipment have become even cleaner since they must now meet California's latest regulations: Gas-powered mowers built as of January 2007 and ride-on mowers starting in January 2008 must hack another 40 percent off their exhaust emissions and 90 percent from evaporative fuel emissions. Similar federal rules are expected for the rest of the country by 2011 or 2012. While mowers and other small-engine power equipment contribute far fewer emissions overall than cars and trucks, the average walk-behind mower pollutes 11 times as much per hour, according to the federal Environmental Protection Agency.
A carbon filter system and less-porous fuel tanks and lines are the relatively straightforward tools engine makers use to meet the new evaporative-emission rules. Manufacturers are also redesigning engines to cut what comes out of their exhausts. While those fixes could cost as little as $15 per mower, engine makers say the tally could climb to $100 and as much as $200 if they add catalytic converters similar to those used in cars. A 2006 EPA study concluded that a catalyst's hotter temperatures wouldn't pose a threat to consumers. Nonetheless, the heat and higher price of catalysts have pushed Briggs & Stratton and other engine manufacturers toward alternative solutions—at least for now.
You don't have to wait for cleaner mowers and tractors to make your lawn-care routine a little greener. Some tips from our experts:
Buy a no-spill gas can. These environmentally friendlier containers reduce evaporative emissions, ground pollution, and wasted fuel. Also be sure to fill the fuel tank only three-quarters full, allowing room for expansion without overflowing.
Don't buy more mower than you need. A walk-behind mower, particularly a self-propelled version, is fine for most lawns and uses less fuel than a larger tractor.
Consider a corded or even a cordless electric mower if you have a small, flat lawn. Both types offer push-button starting and create no exhaust emissions. Manual reel mowers are also a greener choice for smaller spaces, though cutting performance hasn't matched rotary mowers in our tests.
Keep gas-powered mowers and tractors running properly. Change the oil each mowing season, draining the crankcase and refilling it with manufacturer-recommended oil. Replace the spark plug or plugs, clean or replace the air filter, and sharpen the blades to save fuel and cut the lawn, rather than tear it.
Reduce the size of your lawn. Besides saving time and money (about $700 per acre per year for maintenance), smaller lawns mean fewer mower emissions because you mow less. Alternatives include replacing a portion of lawn with ivy and other types of ground cover or landscaping.