Hi Sara,

I’m reaching out to learn if you offer any guidance/support/irrefutable facts re: gas-powered leaf blowers.

I am presenting the information to my town so they’ll consider a ban. The leaf blowers committee is arguing that town board members can be leaders in response to climate change.

As you probably have heard, this ban is picking up steam in towns, counties, and even some states around the country. I live in one of the little towns where the noise is incessant and the smell penetrates my home even with my windows closed.

Can you direct me to sources where I could learn more about the health effects of these heavily polluting two-stroke gas engines?

Many thanks,
Jody in New York

Hi Jody,

You ask for irrefutable facts, so here’s one: The world is awash in amazing sources of knowledge and also gushing sewers of ill-informed comments, misplaced speculation, and outright disinformation fed by deliberate bad faith.

I’ve spent my career learning to sift through fake news and wild-eyed claims about global warming in order to share reputable information with the public. So in addition to pointing you toward resources on leaf blowers, I’m going to walk you through the process I use when I’m learning about a science topic new to me — whether that’s climate change, leaf blowers, or if coffee is good for me.

Find an overview of the topic

When I’m absorbing information about a new topic, it’s easy to feel overwhelmed. So I familiarize myself with its broad outlines by first reading overviews of the issue, usually in well-regarded, mainstream news outlets. Wikipedia can also provide an entry point, though treat anything you read there — particularly the uncited claims — with a heaping dose of skepticism.

You can search for news articles using a database such as Nexis or Factiva, which may be available through your local library. You can also look for recent news articles using the search bar on Google News.

On the topic of leaf blowers, I situated myself by reading an article by James Fallows, a writer for The Atlantic who worked with neighbors on a successful effort to ban gas-powered leaf blowers in Washington, D.C. He offers a helpful explanation of the air pollution generated by the two-stroke engine found in many blowers: “It’s simpler, cheaper, and lighter than the four-stroke engines of most modern cars, and has a better power-to-weight ratio. But it is vastly dirtier and less fuel-efficient, because by design it sloshes together a mixture of gasoline and oil in the combustion chamber and then spews out as much as one-third of that fuel as an unburned aerosol.”

Seek statements and reports by respected institutions

Institutions tend to move slowly and cautiously. When you’re looking for well-grounded facts, that caution is a virtue. Any statement released under the imprimatur of a well-respected institution has likely passed several levels of review and is supported by that organization’s experts. Such institutional statements, for example, have been used to demonstrate the widespread scientific consensus that recent climate change is real and primarily human-caused.

Google makes it easy to search an institution’s website; to find information about leaf blowers on the U.S. EPA’s website, I used this search string: “leaf blowers” site:epa.gov

When I trawled the website of the California Air Resources Board, an agency charged with protecting air quality in the Golden State, I found a recent report that includes a remarkable fact. Owing in part to California’s stringent vehicle regulations, small off-road engines such as those found in gas-powered leaf blowers are a larger source of smog-forming emissions than the state’s 14.4 million passenger cars. As Fallows puts it: “Two-stroke engines are that dirty. Cars have become that clean.”

According to the New York State Department of Environmental Conservation, exhaust from gas-powered leaf blowers contains hydrocarbons and nitrogen oxides — components of smog — plus carbon monoxide and particulate matter, all of which are known to harm people’s health. Nitrous oxide is an extraordinarily potent heat-trapping gas, so leaf-blower exhaust also contributes to climate change, which has its own health consequences. (Click the links for reputable information about each of the pollutants.)

As anyone who has ever used a leaf blower can attest, their 200-mile-an-hour winds also spin up clouds of dust. That dust can contain pollen, mold, animal feces, heavy metals, and chemicals from herbicides and pesticides, according to the Department of Environmental Conservation.

Seek out peer-reviewed research

When you’re panning for reliable information, peer-reviewed articles are lumps of gold. Such articles are published only after experts in the field review them for potential errors. Like anything written by human beings, peer-reviewed articles may still contain inaccuracies, but they are orders of magnitude more trustworthy than that meme shared in the comments of your uncle’s Facebook page.

I’m fortunate to have access to Yale University’s electronic databases of peer-reviewed articles. You may be able to log in to a database of scholarly publications through your local public or university library. (A state-funded university in my area offers community members access to such databases for the price of a $25 library card.) PubMed and Google Scholar are also useful resources.

In my searches, I found several peer-reviewed articles about the loud, low-frequency rumble generated by gas-powered leaf blowers, which poses risks to workers’ hearing. It easily penetrates windows and glass doors of homes, exposing “large numbers of people in the community to harmful levels of noise,” according to a 2018 study. The whine of leaf blower engines contributes to modern life’s cacophony, which health researchers increasingly warn is more than just a nuisance — it can contribute to cardiovascular disease and other health problems.

Given that gas-powered leaf blowers are known to spew a variety of pollutants, I expected that my searches would also turn up peer-reviewed studies on their effects on air quality. To my surprise, I found little beyond a study conducted in Cartagena, Italy, in which researchers found that leaf blowers used for street sweeping created a dust wave that more than doubled the levels of particulate matter in the immediate area for several minutes.

“Unfortunately, this is not a well-funded area,” said Jamie Banks, a scientist and founder of Quiet Communities, Inc., a nonprofit organization that has helped communities push back against noise from landscaping equipment. “The literature is very limited.”

Banks is working to change that. She collaborated with an environmental engineer at the Environmental Protection Agency on a 2015 assessment of the pollution produced by lawn and garden equipment. That analysis estimated that gas-powered lawn and garden equipment generated more than 26 million tons of pollutants in 2011, making them “an important source of toxic and carcinogenic exhaust” and fine particulate matter.

What’s the alternative?

We know that leaf blowers are noisy and polluting, but there’s more work to be done to measure the impact on workers and communities. In the meantime, if you have a lawn, you can make it quieter, cleaner, and more friendly to the climate.

Retired horticulturalist Craig K. Chandler advises simply leaving leaves in place, where they’ll gradually break down and improve the fertility and water-retention capacity of the soil. Leaf litter provides a winter shelter for beneficial insects, which are facing new pressures in some regions as a result of climate change. A robust insect population will also attract birds to your yard, because most species feed bugs to their chicks.

If you don’t like the look of brown leaves in your yard, Chandler recommends a practice called leaf-mulching, in which you simply mow over the leaves to chop them into small pieces that decay quickly. Leaf-mulching can be accomplished with most regular lawnmowers, according to a Bedford, New York-based organization known as Leave Leaves Alone, which was founded by Cornell Cooperative Extension master gardeners and other Bedford residents. I recommend using an electric lawnmower rather than a gas-powered one to reduce noise and fumes.

Whether you let them remain in place or mulch them, the fallen leaves of autumn will contribute to a more beautiful — and peaceful — spring.


Got a question about climate change? Send it to sara@yaleclimateconnections.org. Questions may be edited for length and clarity.

Tom Toro is a cartoonist and writer who has published over 200 cartoons in The New Yorker since 2010.

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Sara Peach is the editor-in-chief of Yale Climate Connections. She is an environmental journalist whose work has appeared in National Geographic, Scientific American, Environmental Health News, Grist,...