How do leaf blowers work?
Leaf blowers have fan blades that draw in a large amount of air from vents in the back of the machine, then shoot it down a narrow tube at speeds that can exceed 200 miles per hour. The expelled air lifts leaves, grass, dust, and debris off the ground and pushes it all forward.
Most gas models use basic two-stroke engines that burn a mixture of oil and gasoline, generating high levels of carcinogenic and ozone-forming pollutants. About 30% of the oil and gas mixture does not burn and is emitted directly as aerosol exhaust.
Battery-powered and corded leaf blowers have electric motors that do not produce the toxic emissions that gas-powered models generate.
How much noise do gas leaf blowers generate?
Typical commercial gas-powered models generate sound that can reach up to 110 decibels at the point of origin, which can cause permanent hearing loss in less than 5 minutes. Unlike most lawn and garden equipment, the sound that gas leaf blowers create is especially powerful in low-frequency elements; this allows the sound to carry for long distances and through building walls. Visit our Resources pages to learn more.
Why doesn’t closing my windows seem to help?
Gas leaf blowers produce sound that is unusually strong in low-frequency elements. In addition to traveling much farther than high-frequency sound, low-frequency sound penetrates walls, windows, and other physical barriers relatively easily.
How does noise affect the ability to think, learn, and work?
Ambient sound levels as low as 45 decibels have been shown to affect the brain in ways that disrupt concentration, cognition, productivity, and learning. A single gas leaf blower produces so much sound energy that it can travel more than the length of two football fields before it dissipates to this level.
Children are especially vulnerable to high levels of environmental noise, with well-documented effects on speech processing, language acquisition, reading comprehension, among other developmental markers. Visit our Research page to learn more.
How does noise affect health?
Noise can affect human health in many ways, and hearing loss is only one of them. Multiple studies have linked chronic exposure to noise above 55 decibels to a variety of non-auditory health problems, including cardiovascular disease, obesity, diabetes, reproductive issues, and mental health disorders. This is why ambient noise is increasingly called “the new secondhand smoke.” Visit our Research page to learn more.
How do the emissions from gas leaf blowers harm human health?
Most gas leaf blowers, both for commercial and homeowner use, run on cheap, highly inefficient “two-stroke” engines — the same type used in many chainsaws and string trimmers. Two-stroke engines, which are being phased out in countries all over the world because of how dirty they are, produce high levels of ozone-forming and cancer-causing emissions, including fine particulate matter, volatile organic compounds (VOCs) such as benzene and formaldehyde, nitrogen oxides, and carbon monoxide.
The California Air Resources Board has concluded that operating the best-selling commercial leaf blower for one hour emits as much smog-forming pollution as driving 1,100 miles in a 2017 Toyota Camry.
Thousands of studies have linked exposure to these chemicals and particulates to an alarming range of health effects, including respiratory disorders, heart attack and cardiac arrest, stroke, cancer, and premature death. Emerging research also suggests links to infant mortality, birth defects, and the severity of asthma in children. A recent study from Harvard public health researchers linked these and other air pollutants to higher risk of death from COVID-19. Visit our Research page to learn more.
Do leaf blowers harm pets and other animals outside?
Yes, they can. Particulate matter in the air is well known to cause challenges for dogs, cats, and other animals. Leaf blowers kick up large clouds of fine dust, mold, pollen, dried animal feces, and other particulates, and these can linger in the air for hours. Pets may exhibit symptoms such as coughing and wheezing, eye discharge, nasal discomfort, and itchy skin.
Further, the loud noises that gas leaf blowers produce can trigger physiological and behavioral stress responses in animals, especially in cats. Over time, these responses increase the risk of health problems such as urinary tract disease, gastrointestinal disease, and others.
What else can I do with my grass clippings and leaves?
Horticultural experts recommend that grass clippings should be left in place to replenish nitrogen in your soil. If you do not use herbicides, you can also capture them in a bag attachment and use them as mulch in your containers or add them to your compost bin.
Fallen leaves are so useful in the yard that it’s a shame to let them blow away, let alone be loaded on a truck and carted off. You can mulch them right in place using your mower, replenishing nutrients in the soil and helping prevent weed growth. You can also use them as a natural mulch around your trees, shrubs, and perennial plants, whether in fall or saved in a dry place for spring.
Learn more about the horticultural benefits and uses of fallen leaves on our Quiet Alternatives page.
Aren’t battery-electric leaf blowers almost as loud as gas?
No. Rigorous field testing of leading commercial models of both types found that gas leaf blowers produced up to 20 times the sound intensity of comparable battery-electric models at a range of distances. This translates to a difference in perceived loudness of about 4 times.
Aren’t battery-electric leaf blowers pretty weak?
This used to be true, but times have changed. The last 10 years have seen a revolution in battery technology, and today virtually all the leading manufacturers of home and commercial lawn and garden equipment offer battery-electric models that match or come extremely close to matching the performance of their gas-powered counterparts. Moreover, the battery tools promise much lower operating costs. Learn more on our Quiet Alternatives page.
Won’t reducing gas leaf blower use put landscapers out of business or cause job losses?
We are not advocating for solutions that would require landscape crews to spend more time on each job.
First, many of the tasks that leaf blowers help accomplish (e.g., removing grass clippings and stray leaves) can actually be harmful for lawns and gardens, and one option is simply to stop doing them, especially in spring and summer. Many landscapers have already moved in this direction. Find out more on our Quiet Alternatives page.
Second, for other tasks such as clearing hard surfaces and gathering large amounts of leaves in fall, we recognize the importance of speed and efficiency. We advocate using a combination of commercial-grade battery-electric and manual tools, depending on the size of the job.
Third, it is true that transitioning to battery-electric tools requires some upfront investment, but by virtually eliminating operating costs for gasoline, oil, filters, and the like, these machines can quickly pay for themselves and benefit the bottom line going forward.
Finally, it is of course the workers who operate these machines for hours each day who face the greatest short- and long-term health risks from the clouds of pollutants and fine particulates, the spray of unburned gasoline and oil, and the ear-splitting noise. They are very often immigrants who work for low wages with no health insurance and little job security as the cumulative effects of chronic exposure mount. Shifting to quieter, healthier, greener alternatives would substantially improve labor conditions even while reducing operating costs.
Isn’t this just a “first-world problem,” for privileged people with too much time on their hands?
On the contrary: indifference to the public-health and environmental-justice aspects of this issue reflects more of a “first-world” attitude.
For the householders who hire lawn crews, the emissions and noise of two-stroke engines are a momentary inconvenience — or one they don’t notice at all, if they hire crews to do the work while they are off at work or otherwise away from their homes.
The people most at risk of health damage from gas-engine emissions, the spray of fine particulates, and ear-damaging noise are the lawn workers who may be handling this equipment many hours a day, many days a week. In major cities the members of hired lawn crews are typically low-wage, non-English speaking, and unlikely to be covered by health insurance; often they use the equipment without ear or nose protection. Indifference to this dangerous equipment implicitly means discounting their long-term health concerns.
Is there any realistic alternative?
Definitely yes, and increasingly so. The revolution in battery technology is one of the fastest-developing fields of high-tech improvement. The demand for battery-powered transportation systems, from cars to aircraft, and the ceaseless expansion of battery-powered mobile equipment is rapidly driving down the cost and weight, and driving up the power and durability, of portable batteries. Lawn-equipment manufacturers are responding with a rapid sequence of new clean, dramatically quieter leaf blowers and other equipment. And many cities across the country, including at least 25 in California alone, have already mandated this shift.
Is noise any more than a nuisance?
Yes. Increasing public-health evidence shows that rising exposure to urban and suburban noise has measurable effects on physical and mental health, especially in children and older populations. View this study for more information: Environmental Noise Pollution in the United States: Developing an Effective Public Health Response.
Apart from the effects on workers, are any other groups of people especially vulnerable to the effects of this outdated equipment?
Yes. As with many other environmental stressors, very young and very old people are the most susceptible. Precisely because their bodies are developing so quickly, children can be disproportionately affected by fumes, aerosol contaminants, dust, and even noise.
A joint letter from doctors in the Pediatric Environmental Health Unit at Mt. Sinai hospital, urging a ban on gas-powered leaf blowers, listed a range of their harmful effects on children. It included this passage about noise:
“The intense, high frequency noise that leaf blowers generate can cause loss of hearing in the workers who operate these machines and can also affect hearing in children and other persons. The ears of infants and young children are especially vulnerable to the high intensity noise that leaf blowers produce because their auditory systems are undergoing rapid growth and development, and these developmental processes are easily disrupted.”
How can lawn equipment be important enough to care about?
Compared with trucks, automobiles, and power plants, two-stroke engines are a relatively small portion of total fossil-fuel use and polluting emissions. But they are an anomaly on the modern environmental scene: At a time when car, truck, and aircraft engines are becoming dramatically cleaner and more efficient, and when power plants are moving to more sustainable energy sources, two-stroke engines are grossly dirty, dangerous, wasteful, and polluting. The easiest benchmark comparison: using a standard two-stroke engine for 30 minutes puts out as much dangerous aerial pollutants as driving a modern Ford F-150 pickup truck for some 3800 miles.
Because of their dirty inefficiency, two-stroke engines have been phased out of nearly all uses other than lawn equipment. The National Park Service has outlawed them for most boat engines on public waters. Scooter and motorcycle makers have moved beyond them. As part of their environmental clean-up plans, many Asian and Latin American cities with serious air pollution problems have outlawed two-stroke engines. These bans have taken effect in cities in India, Indonesia, the Philippines, Thailand, and many Latin American countries. Systems too dirty for the people of Bangkok or Manila have outlived their usefulness in Washington D.C.
Have other cities tried this approach?
Yes, and the number is increasing. More than 100 cities around the country have strong regulations in place to limit or ban the use of gas leaf blowers. The nearby town of Maplewood, for example, bans commercial use of gas leaf blowers for much of the spring, with tough penalties for violations. On a larger scale, the city of Washington, DC recently enacted a year-round ban that will take effect on January 1, 2022. In September 2020, the village of Larchmont, NY, also enacted a year-round ban to take effect in 2022.
What can I do next?
For information on the public-health, environmental, technological, and economic arguments in favor of helping your city shift to cleaner, quieter equipment, please contact us here.