More garbage by the curb. This time it looks like a leaf blower that has outlived its usefulness. Leaf blowers are marvelous inventions for lawn care crews who need to clean a yard or parking lot quickly and easily. However, the noise of their motors can also be a nuisance, especially if they are turned on early in the morning. Many a sound-sleeping neighbor has awakened to the deafening roar of a leaf blower. I cannot say I have had much experience with leaf blowers, but in one part of the landscaping around my deck, there are small, smooth river stones which often get cluttered with leaves. For this one area, a leaf blower works like a charm. I can imagine there are many other landscaped areas which also benefit from this motorized invention. Let’s learn more about it.
According to Wikipedia, a leaf blower, commonly known as a blower, is a gardening tool that propels air out of a nozzle to move debris such as leaves and grass cuttings. Leaf blowers are powered by electric or gasoline motors. Gasoline models have traditionally been two-stroke engines, but four-stroke engines were recently introduced to partially address air pollution concerns. Leaf blowers are typically self-contained handheld units or backpack mounted units with a handheld wand. The latter is more ergonomic for prolonged use. Larger units may rest on wheels and even use a motor for propulsion. These are sometimes called "walk behind leaf blowers" because they must be pushed by hand to be operated.
Some units called blower vacs can also suck in leaves and small twigs via a vacuum and shred them into a bag.
Overview
Drought conditions in California facilitated acceptance of the leaf blower as the use of water for many garden clean-up tasks was prohibited. Leaf blowers also save time compared to a broom. By 1990, annual sales were over 800,000 in the U.S., and the tool had become a ubiquitous gardening implement.
Other functions beyond the simple use of garden maintenance have been demonstrated by Richard Hammond on the Brainiac television series, in which a man-sized hovercraft was constructed from a leaf blower. Being both portable and able to generate wind speeds of between 140–270 miles per hour and air volumes of 14 cubic meters per minute, the leaf blower has many potential uses in amateur construction projects.
The origin of the leaf blower originated in 1947 as a backpack fogger apparatus, invented by Japanese-based Kyoritsu Noki Co. Kyoritsu followed that design with a backpack/blower/misting machine in 1955. in 1968, Kyoritsu applied for patent on a backpack blower mister design, and in 1972 established themselves in the United States as Kioritz Corporation of America and is said to have invented the first leaf blower in 1977. The company changed their name to Echo in 1978.
Among such rival manufacturers as Stihl, Weed Eater and Husqvarna, Echo saw the sales of leaf blowers in the 1970s explode. It is estimated that the sale of leaf blowers in the U.S. had exceeded 1 million units by 1989.
Environmental and occupational impact
Emissions from gasoline-powered grounds-keeping equipment in general are a source of air pollution and more immediately — when powered by internal combustion engines, rather than by electricity — noise pollution. In the United States, U.S. emission standards prescribe maximum emissions from small engines. The two-stroke engines used in most leaf blowers operate by mixing gasoline with oil and a third of this mixture is not burned but emitted as an aerosol exhaust. These pollutants have been linked to cancer, heart disease and asthma. A 2011 study found that the amount of non-methane volatile organic compound pollutants emitted by a leaf blower operated for 30 minutes is comparable to the amount emitted by a Ford F-150 pickup truck driving from Texas to Alaska.
In addition to the adverse health effects of carbon monoxide, nitrogen oxides, hydrocarbons and particulates generated in the exhaust gas of the gasoline-powered engines, leaf blowers pose problems related to dust raised by the powerful flow of air. Dust clouds caused by leaf blowers contain potentially harmful substances such as pesticides, mold and animal fecal matter that may cause irritation, allergies and disease.
Noise pollution is also a concern with leaf blowers, as they can emit noise levels above those required to cause hearing loss to both the operator and those nearby.
Leaf blowers also present an occupational hearing hazard to the nearly 1 million people who work in lawn service and groundskeeping. A recent study assessed the occupational noise exposure among groundskeepers at several North Carolina public universities and found noise levels from leaf blowers averaging 89 A-weighted decibels or dB(A) and maximum sound pressure levels reaching 106 dB(A), both far exceeding the National Institute for Occupational Safety and Health recommended exposure limit of 85 dB(A).
Bans
Soon after the leaf blower was introduced into the U.S., its use was banned in two California cities — Carmel-by-the-Sea in 1975 and Beverly Hills in 1978 — as a noise nuisance. There are currently 20 California cities that have banned leaf blowers, sometimes only within residential neighborhoods and usually targeting gasoline-powered equipment. Another 80 cities have ordinances on the books restricting either usage or noise level or both.
Quieter solutions
To meet the 1995 California regulations for noise and air pollution, leaf blower manufacturers modified the current engine designs to comply. However, 1999 regulations were far more stringent, forcing the engineering of a quieter, more compliant 2-stroke engine design. While leaf blowers were becoming more tolerable in U.S. suburban neighborhoods, many communities had by now in fact, banned their use. In the mid-2000s and to further answer critics, manufacturers once again evolved the leaf blower, with the use of nickel-cadmium or NiCad-powered tool design to create the first cordless leaf blower. The new NiCad battery-powered leaf blower designs were further improved by way of the more powerful and longer run time lithium-ion batteries, which incorporate most cordless leaf blowers marketed today. Cordless leaf blowers today operate with zero emissions and operate at an estimated 70% noise reduction, compared to levels produced by their predecessors.
According to James Fallows’ April 2019 article “Get Off My Lawn” in The Atlantic, he learned several things that changed his thinking about leaf blowers — and politics. Based in Washington, D.C., he discovered that because the technology of gasoline-powered leaf blowers is so crude and so old, the level of pollution is off the charts.
When people encounter engines these days, they’re generally seeing the outcome of decades of intense work toward higher efficiency. The latest models of jet-turbine engines are up to 80 percent more fuel-efficient than their 1950s counterparts. While power plants burning natural gas obviously emit more carbon than wind or solar facilities, they emit about half as much as coal-fired plants. Today, the average car on America’s streets is almost 200 percent more efficient than in 1950, and smog-causing emissions from cars are about 99 percent lower.
The great outlier here is a piece of obsolete machinery Americans encounter mainly in lawn-care equipment: the humble “two-stroke engine.” 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. If you’ve seen a tuk‑tuk, one of the noisy tricycle-style taxis in places such as Bangkok and Jakarta, with purple smoke wafting out of its tailpipe, you’ve seen a two-stroke engine in action.
But you won’t see as many of them in those cities anymore, because governments in Asia and elsewhere have been banning and phasing out two-stroke engines on antipollution grounds. In 2014 a study published in Nature Communications found that volatile organic compound emissions — a variety of carbon gases that can produce smog and harm human beings — were on average 124 times higher from an idling two-stroke scooter than from a truck or a car. With respect to benzene, a carcinogenic pollutant, the group found that each cubic meter of exhaust from an idling two-stroke scooter contained 60,000 times the safe level of exposure. Two-stroke engines have largely disappeared from the scooter, moped and trail-bike markets in America. Regulators around the world are pushing older two-stroke engines toward extinction.
Yet they remain the propulsive force behind the 200-mph winds coming out of many backpack leaf blowers. As a product category, this is a narrow one. But the impact of these little machines is significant. In 2017, the California Air Resources Board issued a warning that may seem incredible but has not been seriously challenged: By 2020, gas-powered leaf blowers, lawn mowers and similar equipment in the state could produce more ozone pollution than all the millions of cars in California combined. Two-stroke engines are that dirty. Cars have become that clean.
According to a 2017 report from the Centers for Disease Control and Prevention, one-quarter of Americans ages 20 to 69 who reported good to excellent hearing actually had diminished hearing. This is largely caused by rising levels of ambient urban noise — sirens, traffic, construction, leaf blowers — which can lead to a range of disorders from high blood pressure to depression to heart disease. “When I started out, I’d see people in their 60s with hearing problems,” says Robert Meyers, an ENT specialist at the University of Illinois at Chicago. “Now I’m seeing them in their 40s.”
Leaf blowers are especially insidious. Something about their sound had long attracted my attention. A study organized by Jamie Banks, a scientist and the founder of Quiet Communities, a Boston-area nonprofit, quantified what it was. Acoustic engineers from a firm called Arup compared gas- and battery-powered blowers with equal manufacturer-rated noise levels. Their analysis showed that gas-powered 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. The acoustic study found that in a densely settled neighborhood, a gas-powered blower rated at, say, 75 decibels of noisiness can affect up to 15 times as many households as a battery-powered blower with the same 75-decibel rating.
Hearing damage is cumulative. When the tiny, sound-sensing hairlike cells, called stereocilia, in the inner ear are damaged — usually by extended exposure to sounds of 85 decibels or above — they are generally gone for good. For the landscapers and homeowners who use gas-powered blowers — a foot away from their ears — the most powerful can produce sounds of 100 decibels or more. ENT specialist Meyers said, “Each time I see these crews, I think to myself: 10 years from now, they’ll be on the path to premature deafness."
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