On a sunny autumn morning, our neighbor and her woodwind quintet were rehearsing in her backyard. I was outside with our two black cats, enjoying the crisp fresh air and the uplifting rendition of Mozart’s Divertimento No. 14. Then, in a yard a couple of houses down the street, leaf blowers roared to life, fortissimo, their ear-splitting cacophony drowning out all other sounds. Propelled by the leaf blowers’ 200-mph winds, noxious exhaust drifted down the block.

At jackhammer-like noise levels that can exceed 100 decibels, leaf blowers damage the hearing of those who use them. The noise triggers headaches; the fumes can cause asthmatic reactions a block away. The sound makes it harder for blind people to get around safely, as they rely on hearing cars and other potential hazards. And for the increasing number of people working at home, the blaring of leaf blowers makes it hard to focus on work tasks or engage in Zoom meetings.

But it’s the outsize level of polluting emissions that has led California to pass a bill that will by 2024 halt the sale of most gas-powered leaf blowers, lawn mowers, and other small off-road engines (aptly known as SOREs). The two-stroke engine employed by leaf blowers combines gas and oil to give the machine more power. This makes it light enough to carry, but two-strokes spit out as much as a third of this fuel mix as unburned aerosol.

Operating a commercial leaf blower for just one hour emits smog-forming pollution comparable to driving a new passenger car about 1,100 miles, roughly the distance from Los Angeles to Denver, more than 15 hours of driving. That fact comes from the California Air Resources Board (CARB), which in 2015 initiated research that supported the passage in October of A.B. 1346, authored by Assemblymember Marc Berman, whose district ranges from Palo Alto to Half Moon Bay.

In an email interview, Berman called leaf blowers and other SOREs a “major air pollution and public health burden,” and noted that this year “smog-forming emissions from small off-road engines surpassed emissions from passenger cars in California.” Think about that: Leaf blowers, generators, lawn mowers, and the like emitted more pollution statewide than California’s 14 million cars. While the state has done an admirable job limiting auto emissions, it hasn’t been able to contain the disproportionate pollution belched up by non-vehicular motors.

While A.B. 1346 will greatly reduce (though not entirely eliminate) the sale of SOREs, existing gas-powered yard equipment can be used indefinitely. When the bill passed, there were headlines—such as “California Enacts Ban on Gas-Powered Lawn Mowers, Leaf Blowers” in Car and Driver—that suggested people could no longer use their existing equipment. That’s false and led to angry comments such as this one posted below that story: “It's just a matter of time before CA comes for the candles on your birthday cake.”

Those most at risk are the gardeners who work for commercial companies. Many of them are immigrants who don’t have other employment options; they work, day in and day out, with leaf blowers just inches from their lungs and ears. A CARB exposure study found that operators of gas-powered devices could “potentially double their current cancer risk from carcinogens emitted by gas equipment.” 

CARB’s analysis projected that the transition to zero-emission equipment will yield $8.8 billion in health benefits in the next two decades and 892 fewer premature deaths due to cardiopulmonary causes. That’s staggering: In California, hundreds of people are dying every decade for the sake of blowing leaves and cutting grass. 

Yet the damage inflicted by leaf blowers goes well beyond physical. “The soul experiences mechanical sounds as an assault,” said retired psychotherapist Larry Robinson. “The soul longs for quiet. I don’t mean merely the absence of sound, but rather the context in which to experience and process subtle audial cues that connect us in a deeper way to both inner and outer worlds.” The sound from gas leaf blowers is “especially painful to the soul because it is of a frequency that is almost impossible for the human brain to ignore,” Robinson said. “It overwhelms all other sounds, including music, conversation, the wind through the trees, or the songs of birds. Absent these, our human lives are diminished.”

Given the emergency the world faces, leaf blowers and other SOREs are “low-hanging fruit in our collective efforts to dramatically cut climate pollution,” says Ellie Cohen, CEO of the Climate Center, a policy-action group based in Santa Rosa, California. She notes that these can be easily replaced by electric yard equipment, whose performance has improved dramatically during the past few years. “As more people experience the electric versions, it is likely the old gas versions will rapidly phase out,” she said, not just in California but around the country. 

Makita, a leading manufacturer of yard maintenance equipment, said it will “cease production of all gas-powered equipment worldwide” by this March, reported The Washington Post.

Christopher Dilbeck, a testing and certification manager for CARB, notes that even when leaf blowers and other SOREs are idle, they’re polluting because fuel is evaporating. But he emphasized that the new regulations aren’t intended to stop people from using equipment they already own. Unlike cars, yard equipment isn’t licensed, which makes it difficult to regulate. 

On December 9, CARB is expected to set 2024 as the phase-out date for the sale of new gas-powered leaf blowers and most other SOREs. The date for gas generators is set for 2028. Could there be a run on these before their sale is restricted? Possibly, Dilbeck said, but halting the sale of this equipment is the best the state can do. 

Beyond the lack of practical enforcement tools, there are equity issues: The state wouldn’t want to require gardeners to buy new equipment. Given that the bill barely passed, a stricter bill probably wouldn’t have moved forward. And people will still be able to buy leaf blowers and mowers in other states and legally bring them into California. So as dangerous as gas leaf blowers are, for human health and the global climate, there will be millions of them in use for years to come. 

Firing up a gas leaf blower someday may be viewed as unacceptable as lighting a cigarette in a nursery school, but that will require education. Dozens of California cities have sought to restrict the use of gas-powered leaf blowers, and journalist James Fallows led a successful crusade to get them banned in Washington, DC. That ban goes into effect January 1, 2022.

In a 2019 story for The Atlantic, Fallows noted that gas-powered leaf blowers produce far more “sound energy” in the low-frequency range. “This may seem benign—who doesn’t like a nice basso profundo?—but it has a surprising consequence. High-frequency sound—a mosquito’s buzz, a dental drill—gets your attention, but it does not travel. It falls off rapidly with distance and struggles to penetrate barriers. If you’re in the next room, you may not hear it at all. By contrast, low-frequency noise has great penetrating power: It goes through walls, cement barriers, and many kinds of hearing-protection devices.”

Hearing loss is caused by both the volume of a sound and the duration one is exposed to noise, says Dr. Jennifer Alyono, an otologist and assistant professor at Stanford Medicine. So gardeners who use this equipment, especially if they don’t wear ear protection, are at greatest risk. Some hearing loss is temporary, some permanent. People who attempt to drown out the noise of leaf blowers by cranking music through headphones could also damage their hearing. Alyono suggests using smartphone apps to measure ambient noise and to protect your ears if the volume approaches 90 decibels.

The case against leaf blowers is clear cut: The noise increases the risk of stroke and is damaging to mental health, especially for people with PTSD. Not everyone goes to bed at 11 P.M. and gets up at 7 A.M., when gardeners are typically allowed to start their engines. Many nurses, firefighters, doctors, police officers, and grocers work the night shift. It’s a nightmare for them to try to get some sleep during the day when leaf blowers are howling. 

“They come in a deafening, surging swarm, blasting from lawn to lawn and filling the air with the stench of gasoline and death,” wrote Margaret Renkl last October in The New York Times. “I would call them mechanical locusts … but that comparison is unfair to locusts.”

Of all the outrages of leaf blowers, this one may be the simplest: They’re unnecessary, even counterproductive. Leaves don’t need to be blown. They can be raked up, swept away, or just left where they fall, to fertilize the ground and bring new life into the world.