It took just three days for the valley air district to sell out of its initial offering of 1,600 clean, electric lawn mowers intended to replace old, pollution-belching gas-powered mowers.

But the effort was so successful the air district is committing an additional $125,000 for 500 more mowers — and hopes to expand the program beginning early next year, said a district spokeswoman.

The Clean Green Yard Machines program sold out of its $400,000 allotment of 1,600 mowers in early November. The second round of funding opens Friday at 8 a.m.

"Because of the overwhelming response to this popular program, we are releasing an additional $125,000," Seyed Sadredin, the district's executive director, said in a release. "We hope to release even more funding after the first of the year once the lawn mower manufacturer has fully caught up with this current overwhelming wave of orders."

The additional funding was authorized by the district's governing board from the 2010-11 budget for community incentive grants.

The lawn mower trade-in program replaces old, polluting gas-powered mowers with clean, electric Neuton mowers for $25 or $50, depending on the model. A single gas-powered mower running for an hour produces about as much pollution as 40 late-model cars, according to the district.

The Neutons retail for $349 and $399 on the company's website. If demand continues, the district anticipates exhausting the additional funding before the end of next week.

The lawn mower trade-in incentive is just one of several efforts funded by the district through a variety of federal, state and local sources, including DMV fees paid by valley residents.

The eight-county air district, which extends from Bakersfield to Stockton, has long included a $7 surcharge on DMV auto registrations in the valley.

The district board voted last month to pay for a multimillion-dollar federal air pollution fine by adding an additional $12 to the annual cost of registering a motor vehicle in the valley.

All of that money, district officials say, will be used to fund anti-pollution programs in the valley.

The $100 million available this year for air-quality incentive programs funds projects involving wood stoves, school buses, trucks, bike paths, vanpools and many other projects designed to reduce emissions.

To participate in the mower-replacement program:

* Call 559-230-5800 and request a voucher for Clean Green Yard Machines.

* After receiving the voucher, take your old gas-powered mower to an authorized recycler near you.

* After turning in your old mower, order your new electric mower by phone. It's delivered to your door with no shipping cost.

For more details, visit Valleyair.org or call the Bakersfield office at 392-5500.