Traditional gas-powered lawn mowers are responsible for 5 percent of the nation's air pollution, according to the Environmental Protection Agency. One gas mower running for an hour emits the same amount of pollutants as eight new cars driving 55 mph for the same amount of time, according to the Union of Concerned Scientists. Even the innocuous Weedeater emits 21 times more emissions than the typical family car, while the leaf blower can emit up to 34 times more according to Eartheasy.com.

All this adds up to about 800 million gallons of gas burned each year in the quest for the perfect patch. But, about 17 million gallons of that fuel doesn't quite make it to the mower tank and winds up spilled on the ground. That's more than the Exxon Valdez spilled in 1989, and chances are that most homeowners do not clean it up. If that spilled fuel is left to evaporate into the air, it forms smog-forming ozone when cooked by heat and sunlight and seeps into our water supply.

If your mower happens to be a two-cycle engine, it releases 25 to 30 percent of its oil and gas unburned into the air, along with particulate matter, carbon dioxide, and other ingredients of smog. This unhealthy soup we breathe contributes to cancer and damages our hearts, lungs, and immune systems.

Want to lessen the environmental impact of your lawn? The "greenest" thing you can do is convert your lawn to a vegetable garden and replace the turf with lovely raised beds of edible greens.

If that is too crunchy for your taste, how about trading in those gas guzzlers for the old-fashioned human-powered kind? Reel mowers are easier to use, quiet, non-polluting and you don't have to worry about spilling the gas. With the money you save on gas alone, you could buy a good pair of clippers for the bushes and a scythe for weed whacking.

If you want to take the work out of lawn care, consider investing in electric mowers and weed whackers. Electric mowers range in price from $150 to $450, and the average cost in electricity to power the mower for one year is about five bucks, with no spilled gas and less emissions. Propane powered lawn equipment is a good choice when your lawn is the size of a golf course.