The Environmental Impact Of Leaf Blowers
Once summer is over & the leaves have fallen, you’ll need to get your leaf blower out of the shed and ready for action. You already know how much it saves your back, compared to raking up leaves by hand, but how much does your leaf blower hurt the environment?
According to the California Air Resources Board, the types of air pollutants emitted when using a gasoline-powered leaf blower for half an hour are equivalent to those emitted from 440 miles of automobile travel at 30mph average speed.
Compared to an average large car, one hour of operation of a leaf blower emits 498 times as much hydrocarbons, 49 times as much particulate matter and 26 times as much carbon monoxide.
U.S. Environmental Protection Agency figures show that 25% of US hydrocarbon emissions are created by small machines, which includes leaf blowers.
Electric motors don't cause any emissions locally (although depending on where your city’s electricity comes from, there will still be some emissions caused somewhere).
The New York State Department of Environmental Conservation says gasoline leaf blowers are responsible for fuel and exhaust emissions including hydrocarbons, oxides of nitrogen, carbon monoxide, and fine particulate matter.
They state the amount of carbon monoxide emitted from a typical gas leaf blower in 1 hour of operation is the same as you’d get from driving a modern car for 8 hours.
You can find more information about small gas engine emissions from the EPA here (pdf).
You may be surprised to find out that your older, less powerful two-stroke leaf blower is a worse polluter than the larger, newer models available today.
That's because the four-stroke engines used on some modern blowers produces about 10% of the pollutants of older two-stroke engines. Not only that, but they are also much quieter than two-stroke engines.
The main disadvantages of four-stroke engines for hand-held power tools is their heavier weight.
Legislation over the last two decades has favored the four-stroke engine, with the result that two-stroke engines are becoming harder to find.
To cut a long story short, if you’re concerned about the environment, but you insist on a gasoline leaf blower, make sure it has a four-stroke engine.
Leaf blowers (both gas and electric) can send dust & other small particles for considerable distances. The particulate matter stirred up by blowers can include such nasties as animal feces, pesticides, chemicals, trace quantities of heavy metals such as lead, as well as allergens such as pollen and mold.
Asthmatics and those suffering from allergies, as well as the elderly & children, are most susceptible to problems caused by airborne dust and particles.
The California Air Resources Board states the following: “..Road dust contains lead at highly toxic levels and up to 20 known allergens. In residential areas of L.A., road dust contributed 5-12% of the allergens in the air.”
The EPA doesn’t currently list or track dust emissions caused by leaf blowers, however it’s estimated that leaf blowers contribute between 1-5% of all airborne particles of 10 micrometres or less.
Leaf Blower Noise
Noise is another problem caused by leaf blowers. Despite only being introduced into the USA in the early 1970s, by 1975 they'd already been banned in one city due to noise. There are now over 80 cities nationwide which have partial or complete leaf blower bans.
The gold standard for leaf blower noise (defined by the ANSI) is 65dB, measured at 50 feet. However, many blowers available today produce over 70dB at 50 feet, which can translate to over 105dB at the user's ears. (A higher number is louder, and every 10dB increase is equivalent to twice as loud)
Anything over 85dB can cause hearing loss; every 3dB increase over 85dB cuts the time taken to cause hearing loss in half; and at 105dB, permanent hearing loss can occur in as little as 4 minutes.
Electric blowers are almost always quieter than gas, however a large part of the noise is caused by air being pushed by a fan, at high speed, through a nozzle. This is unavoidable regardless of which engine type your blower has.
One manufacturer of gas blowers in particular (Echo) has gone to a lot of trouble to make their gas blowers quieter - some of their gas blowers are rated at 64dB, and it also avoids a lot of the characteristic whine, due to careful design of the nozzle and fan. We have reviewed some of their most popular blowers here.
You can find out more about the specific noise issues associated with leaf blowers at leafblowernoise.com.
Nowadays, you can put any environmental guilt to rest by using electric versions. Although they tend to be cheaper than the traditional gas/oil four-stroke blowers, they are generally not as powerful as gas blowers.
These green versions are either mains- or battery-powered, and though they do require electricity, which usually results in emissions somewhere, they do not have the local emissions output of their gasoline equivalents.
With more emphasis being placed on the environment and more research being poured into the area, expect cordless and corded electrical blowers to become more capable and competitive over the next few years.
Click here for more information on the differences between gas & electric blowers.
Hints & Tips
- If you must use a gasoline blower, insist on a 4-stroke engine
- Check the noise ratings and at what distance they're measured, before you buy
- Check the blower is in good working order before using it - clogged filters use more energy
- Use the lowest possible power setting to get the job done. This reduces noise and helps efficiency
- If the area is very dusty, consider using a shovel or yard broom instead
More at the Department of Environmental Conservation website.