Those gas-powered leaf blowers, hedge trimmers and mowers you hear in your neighborhood aren't just annoying — they make a lot of pollution, too.In California, they're about to pass cars as the worst air polluters, spewing out formaldehyde, benzene and particulate matter. According to Michael Benjamin at the California Air Resources Board, in just three years' time, the biggest single ozone polluter in the state is going to be all this gardening equipment."We expect that ozone-contributing pollutants from small off-road engines will exceed those same emissions from cars around the 2020 time frame," Benjamin says.It sounds hard to believe: More pollution from leaf blowers than cars. But in California and across the country, regulations on car exhaust have gotten tighter and tighter over the years, substantially reducing their ozone-damaging emissions. Not so with small gas engines, Benjamin says. And with 16 million of them cranking up across California, all that pollution adds up."Unless ARB adopts more stringent controls, emissions from this category are going to really become much more significant relative to cars," he says.Some states and regional air-quality districts do have incentive programs in place to try to get homeowners to switch from gas to electric machinery.But California — which currently goes by federal standards for its emissions regulations of small off-road gas engines — is considering requiring tougher emissions standards for small gas engines and to offer major incentives for landscaping businesses to change over to electric.David Clegern of the California Air Resources Board says he is unaware of any other states pursuing programs other than exchanges for residential lawn and garden equipment or of other states lobbying the federal Environmental Protection Agency to adopt more stringent standards.Making the switchAt an expansive backyard in western Los Angeles, one business is already starting to make appeals to landscapers with electric equipment. Dan Mabe runs American Green Zone Alliance, and he's trying to reach small, mostly-Latino landscape crews. Here, he has a lawn full of equipment spread out for landscaper Noe Bautista and his workers to test.Bautista has tried to get his crew to wear face masks, but most young Latino workers won't use them — partly because, he says, there's really no way to keep out those fumes."You can feel the gas smell right away. You have a headache right away with all that smoke," he says.Mabe says this is more than an air quality issue. And it even goes beyond the respiratory problems of many gardening workers."You can call it environmental justice. It was a demographic that wasn't really being addressed," Mabe says.As head of this crew, Bautista, for one, is ponying up the cash now and making the switch — not only for health reasons — but since electric equipment means no more buying gas, he thinks he may even save a little money. Copyright 2017 NPR. To see more, visit http://www.npr.org/.