Air district report: Leaf blowers present health risks | News | Mountain View Online |


Air district report: Leaf blowers present health risks


• Read Gas-powered leaf blowers are banned from neighborhoods — so why are they being used everywhere?

• Read What to know about 'mow and blow'

Blasting air at up to 185 mph, leaf blowers can whip up hazardous particles and contaminants from the ground at speeds greater than a Category 5 hurricane, sending them long distances.

Epidemiological studies have long recognized the harm these particles — including hydrocarbons from gasoline, animal droppings, spores, fungi, pollens, pesticides and herbicides, fertilizers, brake-lining dust and tire residue and heavy metals — cause to people's respiratory systems, according to Bay Area Air Quality Management District reports.

Exposure to particulate matter is rarely, if ever, cited as the cause of death in a coroner's report when someone dies of a heart attack or stroke or lung disease, a 2012 district study noted. "However, epidemiological studies indicate that exposure to particulate matter is an important contributing factor in hundreds, perhaps thousands, of deaths in the Bay Area each year."

The district has called particulate matter "the air pollutant that poses by far the greatest health risk to Bay Area residents."

The average adult inhales 450 cubic centimeters (roughly one pint) of air per breath, which includes 1 million to 10 million tiny particles with each breath.

"But that figure can spike to much higher levels in close proximity to high-volume roadways or other major outdoor emission sources," the district's "Bay Area 2010 Clean Air Plan" noted.

The contribution of leaf blowers to air pollution isn't to be underestimated. About 5 pounds of particulate matter per leaf blower per hour are swept into the air and take hours to settle, according to a widely cited leaf-blower pollution report by the Orange County, California grand jury in 1999.

An Air District program aimed at replacing up to 50,000 leaf blowers and 10,000 lawn mowers by 2020 would reduce the most dangerous small-particle emissions (sized 2.5 and 10 microns) by 0.12 tons (240 pounds) per day, according to the 2010 Clean Air Plan.

Fine particles measuring 2.5 microns and coarser material measuring 10 microns are more readily absorbed into the lungs. The smaller 2.5-micron particles are associated with hazardous organic compounds and heavy metals, according to the U.S. Environmental Protection Agency (E.P.A.). Particles measuring 10 microns are typically composed of smoke, dirt, dust, mold, spores and pollen.

Particulates in the 2.5-micron range can migrate many hundreds of miles and stay the air for days or weeks; 10-micron particles can travel up to 30 miles and stay aloft for hours, according the U.S. E.P.A.

Besides what they kick up off the ground, gas-powered leaf blowers themselves emit specific pollutants the State of California has identified as of concern: hydrocarbons from both burned and unburned fuel, which combine with other gases to form ozone; carbon monoxide; and toxic contaminants such as benzene, 1,3-butadiene, acetaldehyde and formaldehyde, according to a widely quoted 2000 California Environmental Protection Agency Air Resources Board report.

The Air Quality District in 2010 estimated there were approximately 258,000 two-stroke leaf blowers in the Bay Area, which generate significantly more air pollution than four-stroke engines.

Testing in 2011 by the vehicle reviewer showed just how dirty leaf blowers remain, even 11 years after new emission standards for blowers went into effect.

Pitting leaf blowers against a Ford F-150 SVT Raptor crew cab, the leaf blowers were the big dogs when it came to spewing non-methane hydrocarbons, oxides of nitrogen and carbon monoxide — the three pollutants that the EPA and the California Air Resources Board find most concerning.

The two-stroke blower generated 23 times the carbon monoxide and nearly 300 times more non-methane hydrocarbons as the truck.

"To equate the hydrocarbon emissions of about a half-hour of yard work with this two-stroke leaf blower, you'd have to drive a Raptor for 3,887 miles, or the distance from northern Texas to Anchorage, Alaska," the article noted.

Officials from local lung-health organizations said the contribution of leaf blowers to pollution can't be ignored.

"It should be of great concern," said Lynn Smith, interim executive director of Breathe California of the Bay Area, also noting the huge discrepancy between leaf blower and car emissions.

Various arguments have been made by some environmental groups that blowers should be entirely banned in favor of a return to old-fashioned brooms and rakes.

A 1999 study by the University of California Riverside and San Joaquin Valley Unified Air Pollution Control District, the first of its kind, attempted to quantify the differences. Leaf blowers produced about 30 milligrams per square meter of 2.5-micron-sized particulates and 80 mg per square meter of 10-micron particles.

The results were similar for push brooms used on a concrete surface, probably because of the smoother surface, the researchers found. But using a push broom on asphalt produced no 2.5-micron particles and only 20 mg in the 10-micron range.

And raking on either surface produced no particulates in either range, the study found.

The California Landscape Contractors Association, however, disputes the allegations of the air pollution caused by leaf blowers, calling concerns over air emissions "spurious," according to a 1999 letter from its board of directors that was confirmed as current on July 20.

"Properly used leaf blowers do not raise inordinate amounts of dust. Rule 403 of the South Coast Air Quality Management District states that 'a person shall not cause or allow the emissions of fugitive dust from any active operation, open storage pile, or disturbed surface area such that the presence of such dust remains visible in the atmosphere beyond the property line of the emission source.' Blower users can and should follow this rule," the letter states.

In addition to arguing that emissions standards from the California Air Resources Board implemented in 2000 would significantly reduce emissions from handheld equipment, the association pointed to the intermittent use of blowers.

"Portable lawn and garden equipment contributes only 0.8 percent of all U.S. VOC (volatile organic compound) emissions, 0.6 percent of carbon monoxide emissions, and no nitrogen oxide emissions."

Debates over air pollution aside, there's also noise — perhaps the most evident pollution caused by leaf blowers. The City of Palo Alto requires leaf blowers to emit no more than 65 decibels, when measured from 50 feet away.

The Occupational Safety and Health Administration (OSHA) has determined that decibel levels above 85 cause permanent hearing loss. The World Health Organization recommends a general outdoor noise level of 55 decibels or less and 45 or less for sleeping restfully.

Excessive noise has been implicated in higher heart-attack rates, gastrointestinal disturbances, sleep problems, social discord and psychological problems, according to the U.S. E.P.A.

Ironically, metal rakes aren't much quieter, though the sound is less constant: The City of Palo Alto noted in a 2005 report that metal rakes used on concrete can generate 58-60 decibels at 50 feet.

When it comes to encouraging gardeners to forego their gas-powered machines, one air quality district in southern California has had significant success with its leaf blower exchange. The South Coast Air Quality Management District, which covers Orange County, urban Los Angeles, San Bernardino and Riverside, has held a leaf blower buy-back program since 2006 for professional gardeners. In that time, the district has put more than 12,000 reduced-noise and lower-emissions leaf blowers in the hands of professional gardeners.

The agency distributes about 1,500 new leaf blowers annually, said spokesman Sam Atwood.

"According to the E.P.A., a commercial blower emits 93 pounds per year of air pollutants. Multiplied out times 12,000, the units we have distributed have reduced 500 tons of pollutants since 2006," he said.

So far, the district has distributed cleaner blowers manufactured by the company Stihl. The company has supplied trainings at the exchanges. Operators learn to use the blower like a broom, rolling the debris from one area to another where it can be collected, rather than blasting it in a cloud of dust, he said.

The district helped support the development of backpack electric leaf blowers, which are just now becoming commercially available, he said. Atwood said the district hopes that it will get at least one proposal this year for a truly zero-emission, battery-powered leaf blower as part of its request for proposals.

"In demos, they seem to work very well, equal at least to a gas-powered blower. But it's a little premature to say how they will compare in the field to their gasoline counterparts," he said.

For its part, the Bay Area Air Quality Management District is running a program to fund the purchase of new, battery-powered, zero-emission electric lawn and garden equipment in exchange for gasoline-powered lawn and garden equipment. The program is currently only operating in Alameda and Contra Costa counties, however.

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10 people like this
Posted by Well yah...
a resident of Bailey Park
on Aug 24, 2015 at 10:27 am

If laws are not enforced, they do not exist.
We have no leaf blower laws and no dog/leash laws... not that I can see anyway.

10 people like this
Posted by Lucy Lawless
a resident of St. Francis Acres
on Aug 24, 2015 at 12:44 pm

Mountain View doesn't have any leaf blower laws so there's nothing to enforce.

6 people like this
Posted by What she said
a resident of Bailey Park
on Aug 24, 2015 at 1:05 pm

and they also have no leash laws.

10 people like this
Posted by Alice
a resident of Monta Loma
on Aug 24, 2015 at 2:29 pm

SEC. 5.50. - Restraint of dogs.
The owner of any dog shall keep and maintain such dog under their own physical restraint by use of a leash not to exceed six (6) feet in length, or shall keep such dog sufficiently confined behind a fence of reasonable height.
(Ord. No. 4.14, § 1, 4/8/14.)

There are exceptions, but that seems pretty clear to me.

7 people like this
Posted by 2 the point
a resident of Bailey Park
on Aug 24, 2015 at 2:42 pm

No no, its about how lack of enforcement = lack of law.
No leash laws are enforced in MV so in reality there is no leash law in MV, despite what someone wrote in a book one day calling it a law. It really does not exist.

34 people like this
Posted by Liz Siegel
a resident of Old Mountain View
on Aug 24, 2015 at 3:05 pm

between the air pollution and the noise pollution why can't we stop the leaf blowers…I have actually been wondering if the city of Mountain View pays the leaf blowers in our neighborhood to clean the streets because they always seem to be blowing stuff down the streets. We have lots of rats and other critters in our neighborhood and the amount of poo that is blown in the air must be amazing. Can't we improve the quality of life in Mountain View with a little less noise and a little less air pollution by banning the blowers. At the very least ban them on the weekends and give us all two days of peace.

36 people like this
Posted by Kevin McBride
a resident of Cuesta Park
on Aug 24, 2015 at 3:15 pm

I would love to see an end to leaf blowers. The noise and air pollution is unacceptable. Gardeners can sweep and rake. Home owners can pay extra if it takes more time.

7 people like this
Posted by kj
a resident of Old Mountain View
on Aug 24, 2015 at 4:30 pm

This article needs to go viral ... but the Title needs to be changed to include the subject matter,
"leaf blowers" and "causing pollution".

23 people like this
Posted by jack H
a resident of Gemello
on Aug 24, 2015 at 4:55 pm

Yes, leaf blower dirties up places real quickly especially in the summer time with windows open all day long.
Good to know it also pollutes the air we breathe which we cannot see until we get health problems.
We should ban the leaf blower, forever.

5 people like this
Posted by Editor
a resident of Old Mountain View
on Aug 24, 2015 at 5:57 pm

kj, You're right about the headline. It's now changed in the news story this thread is linked to. Thanks.

28 people like this
Posted by Eek_a_leaf!
a resident of Cuesta Park
on Aug 25, 2015 at 9:48 am

What is so terrible about brown leaves on the ground that they have to blown and swept up EVERY SINGLE WEEK? This obsession with manically and fastidiously spotless yards is a very Californian phenomenon. In other parts of this country, people are more chill about their yards. Some even appreciate the small reminders of the cycles of nature lying here and there. We rake twice a month. My yard may not be pristine 24/7, but my neighbors can take lots of peaceful, uninterrupted naps -- and, it seems, breath cleaner air too.

19 people like this
Posted by NW Resident
a resident of North Whisman
on Aug 25, 2015 at 9:49 am

What bothers me are the landscaping crews at apartment and condo complexes who use multiple blowers at the same time, on city sidewalks and streets. They often blow debris out into the street and leave it there, which I saw yesterday morning on Devonshire Ave.

It's very annoying when we're trying to take a walk and have to change routes to avoid the blowers. At a minimum, I think the blowers should stay within the property where they're working and not be out in the street.

I also see this occurring in Sunnyvale in the area where I work when folks are trying to walk during the lunch hour, so it's a problem in a lot of places.

25 people like this
Posted by sick of it
a resident of Old Mountain View
on Aug 25, 2015 at 10:10 am

Time for a leafblower ban in our fair community?

24 people like this
Posted by mvresident2003
a resident of Monta Loma
on Aug 25, 2015 at 10:40 am

mvresident2003 is a registered user.

I'm all for a ban. Tied of the noise (I now have planes to contend with), tied of the dirt/dust that comes in my house when they're blowing three house down.

Ban them.

6 people like this
Posted by What's Next
a resident of Cuernavaca
on Aug 25, 2015 at 10:59 am

I'm fine with blowers. Once a week for a few houses in the neighborhood. Big deal. Let gardeners efficiently do their work and make a living.

There are plenty of other things that are more noisy and irritating.

26 people like this
Posted by Rodger
a resident of Sylvan Park
on Aug 25, 2015 at 12:31 pm

All 2 stroke motors should be banned from California. They are terrible for our health and the health of the planet.

It would also be great if leaf blowers were banned.

12 people like this
Posted by OldMV
a resident of Old Mountain View
on Aug 25, 2015 at 4:04 pm

I want peace and quiet our residential neighborhoods. I'd like a strictly enforced ordinance that 1) allows only electric blowers and that bans all non-electric leaf blower use in MV, 2) limits hours of use to 9 AM to 3 PM when most people aren't home to be disturbed, and 3) bans ALL leaf blower use on weekends, when people want quiet weekends. I'd extend the same rules to all non-electric chain saws and also to noisy construction power tools, like table and circular saws, nail guns, hammers, rototillers, tractors, and wood chippers.

11 people like this
Posted by psr
a resident of The Crossings
on Aug 26, 2015 at 11:03 am

I agree with OldMV, at least on point 2 and 3.

I don't really care if the blowers are gas or electric, but I can't stand the noise. Limiting it to between 9 and 3 on weekdays would be great. I would also limit mowing to after 9:00am.

My neighbors are great, but they have a yard guy who blows and mows starting at 8:00am on Saturday mornings, which is my only morning to sleep in or enjoy my house early in the day. My house borders Palo Alto, which DOES have a blower ban and it also seems unfair that they should have tolerate the disturbance as well.

Until there is a law, how about people have a little consideration for their neighbors and make sure your gardeners don't cause noise before 9:00, especially on weekends?

30 people like this
Posted by OldMVMD
a resident of Old Mountain View
on Aug 26, 2015 at 2:43 pm

I have long wondered why we ignore the health risks posed by leaf blowers, since it is evident that they cause particulate air pollution (you can SEE the cloud of dust they leave in the air), regardless of whether or not they are electric. Small particulates, when inhaled, accelerate progression of lung disease (think asthma and emphysema) and also affect cardiovascular disease. People die of heart and lung disease. There are also organisms in the soil--bacteria, viruses, fungi, parasites--that can cause serious infections when inhaled. I cross to the other side of the street to avoid leaf blowers and the air pollution they cause; but the pollution they cause lingers in the air for long after they have finished the job, so there is no avoiding it entirely.

Bring back rakes!

9 people like this
Posted by Act of G
a resident of Old Mountain View
on Aug 26, 2015 at 7:38 pm

We should also ban windy days.

Pollination ticks me off too!

4 people like this
Posted by Mike Laursen
a resident of Monta Loma
on Aug 27, 2015 at 12:06 am

This has the air of faulty analysis and sloppy scientific methodology about it.

Did they compare against any control such as testing how much particulate matter sweeping, or a wind storm, kicks up? Did they consider that, say, a driveway that is cleaned up every week doesn't accumulate massive piles of particulates to be available to be kicked up into he air?

Even if the Air District program wildly succeeds, it will only reduce pariculate pollution by 0.12 tons per day when about 115 tons are generated by other sources. That's insignificant.

11 people like this
Posted by Non Methane Hydrocarbons
a resident of another community
on Aug 27, 2015 at 4:36 am

So if the only effect of the AQMD program is to remove the 2 stroke gas powered leaf blowers, that will have a massive effect on the non methane hydrocarbons. I.e., it's not the actual sweeping but the inefficiency of the powering motor's fuel source that is a big problem.

Also aiming at 4 stroke newer gas powered motors can't hurt as well.

I don't which kind it is, but you can smell the burned gasoline in the air for quite a while after these things are used. Electric motors don't do this.

3 people like this
Posted by NEON
a resident of The Crossings
on Aug 28, 2015 at 3:19 pm


8 people like this
Posted by Mv1980
a resident of Blossom Valley
on Sep 1, 2015 at 9:05 am

Love to see blowers banned in MV. The dust they produce is bad for health and I don't understand why they are not banned already.

7 people like this
Posted by Vittorio
a resident of Rengstorff Park
on Sep 25, 2015 at 9:13 am

Let's learn from the fantastic Los Gatos! And asap
Web Link

3 people like this
Posted by What
a resident of another community
on Nov 18, 2016 at 7:01 am

I live in the community behind Walgreens on the corner of grant and el Camino. The Gardner's start blowing leaves at about 5:30 am! This morning 5 and not at 6:30 the garbage truck is going at 6:30. I have gone out in my jammies to ask him to stop but no habla. When our council is done stroking each other's ego's and destroying what's left of our town maybe they will follow Palo alto, los Altos, Sunnyvale and ban these things.

9 people like this
Posted by Me
a resident of Willowgate
on Nov 18, 2016 at 11:58 am

if a non-existant law gets enforced, does it become real?

7 people like this
Posted by Cici
a resident of another community
on Dec 1, 2016 at 10:37 pm

I live in Walnut Creek, in a small cul de sac. Every Thursday 8am gardener comes with all his trucks and takes over for four to 5 hours blowing 7 houses with a loud monster blower He used to come at 7 which is against ordinance until we fixed that. We have leaf blowers surrounding us 5-6 days a week. It is non stop and We are starting to feel the health and mental effects of this constant noise and dirty pollution. Head ringing, sneezing for hours after they leave.
They refuse to change their ways and it is time for a Gas Leaf Blower Ban to protect our environment and homes. The City does nothing about it. Anyone have thoughts on next step?

3 people like this
Posted by Jean
a resident of another community
on Aug 24, 2017 at 3:13 pm

Although today is the 2nd anniversary of this leaf blower article, the issue remains a concern. In multi cultural, multi unit housing in Santa Clara with no ordinance, our respiratory health is affected (as well as our hearing).

If anyone is still pursuing limiting/eliminating leaf blower use, I would appreciate hearing from them. Also, I wonder if anyone has translated this great article into Chinese or Spanish . . . if so, please let me know.



3 people like this
Posted by Mark
a resident of Another Mountain View Neighborhood
on Aug 25, 2017 at 9:13 am

I don't think there's any action or discussions on this issue at any level that would make a difference. It's business as usual. Respectfully, if you want change, it won't come via the comments section, but I would support a limit on these blowers if the issue gained any traction.

3 people like this
Posted by Jean S.
a resident of another community
on Aug 25, 2017 at 10:43 am

Mark - Thanks for taking the time to reply to my post. Sounds like you are pretty discouraged about anything disrupting "business as usual". I believe that change begins with communication, enabling like minded people to organize, strategize and act in the real world to attempt to improve things. I appreciate your support should I find "traction" elsewhere - but how to let you know?

3 people like this
Posted by Mark
a resident of Another Mountain View Neighborhood
on Aug 25, 2017 at 11:17 am

"Sounds like you are pretty discouraged about anything disrupting "business as usual"

Is that how it sounded? I'm sorry, I must not have been good at communicating. To clarify, I'm a huge proponent of change. Biz as usual when it makes no sense is not good. I'm just not that passionate about the issue compared to other local issues. I was simply stating with lack of passionate interest shown by residents at the council meetings, it very likely will not garner much change and things will go on as before.

The perfect example can be seen by the lack of action or discussions since this topic was first posted. It simply died out. Communication on issues is good, but most effective when done in places that make a difference. Otherwise it's just wasted efforts. Maybe this time is different though. I don't mean to discourage, only inform, so have at it as you wish. I just wouldn't expect much change until the discussions expand to more than the msg boards.

3 people like this
Posted by Jean S.
a resident of another community
on Aug 26, 2017 at 5:32 am

I also observed that after a flurry of concern about the noise and stench of leaf blowers (especially 2-stroke), interest waned. Compared to Climate Change or carnage from gang wars or a nuclear threat, I suppose leaf blowers are almost inconsequential. I wonder what your local issues are that are of more concern to you. As an activist, you are probably aware that people who organize around one activity often have other concerns and sometimes work together to tackle them.

My original post was to see if anyone remained involved in the issue and had access to that article in Spanish and Chinese for use in my own Santa Clara area. Apparently not.

I am curious about how you even noticed my post. You may well be a representative of the leaf blower industry assigned to monitor this topic and subtly discourage others, an effective business tactic. Care to say?

3 people like this
Posted by A. Noid
a resident of Cuernavaca
on Sep 20, 2017 at 10:47 am

If this issue seems like it is not important, please consider the residents who must endure gas powered leaf blower noise constantly outside their windows. Weekdays, weekends, the noise is constant and extremely disruptive to sleep. Electric blowers exist; there is no reason why people's sleep should be disturbed every morning just so some landscapers can loudly blow dust into the air. A leaf blower exchange program coupled with a ban on small gas powered engines such as those used in leaf blowers would work really well for everyone. Or just ban them and throw them all into the recycling. I don't care how it is done, let me sleep.

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