The Air Quality Management District is hoping users of traditional gas-powered lawn mowers will help them "mow down air pollution" when, for the eighth year, the air pollution control agency hosts a series of lawn-mower exchanges throughout Southern California. The program allows local residents to trade in a gasoline mower and receive a new electric mower at a reduced price.

According to William Burke, governing board chairman of the Air Quality Management District, a conventional lawn mower spews more pollution in one year than a car driven more than 20,000 miles. Leaf blowers and other gasoline-powered equipment also contribute to global warming, as a recent UC Irvine study documented.

The gas mowers replaced in the years AQMD has been running its mower exchange program will have avoided adding about 80 tons of smog-forming emissions to the air by the time the 2010 exchange has taken effect, the agency estimates.

The four mowers available through the Mow Down Air Pollution events are manufactured by Neuton and Black & Decker. Models that normally retail for $349 to $499 cost $100 to $165 through the exchange program.

Last year, the AQMD made 4,800 mowers available, all of which sold out. This year, it's increasing the capacity to 9,380 mowers, aided by funding from the California Air Resources Board.

Registration for the program begins at 8 a.m. April 21 and is on a first-come, first-served basis. Residents must pre-register for the mower of their choice at www.aqmd.gov or call (888) 425-6247. They are then given a time to show up at one of the 11 events scheduled between May 1 and July 24 in Palm Desert, Long Beach, Los Angeles, Inglewood, Riverside, Rancho Cucamonga, Anaheim, Pasadena, Pomona, Santa Clarita and Pacoima.

To be eligible for exchange, the gas mowers must be in working order. The scrapped mowers are then recycled through a metal recycling facility.