Lawnmowers and other engines under 50 horsepower account for 7% of smog emissions in California – the equivalent of about 3 million cars.
Bonnie Holmes-Gen with the American Lung Association of California says the new EPA waiver is great news.
"Well, we’re very pleased with the ruling. Off-road engines like lawnmowers and lawn and garden equipment are a big source of smog forming emissions in California. It’s very important that they’re controlled and we strongly support the regulations."
Catalytic converters on lawnmowers could cut smog emissions by roughly 40%.
The California Air Resources Board passed the mower emissions rule three years ago but couldn’t enforce it pending the EPA waiver.