Archive for May 11th, 2008

The Trouble With Leaf Blowers

Sunday, May 11th, 2008

I did a presentation on basic elements of eco-friendly garden design and maintenance at town hall the other day and after the presentation, a woman from Yonkers, NY came up to me and proudly introduced herself as the driving force behind the recent Yonkers leaf blower ban. I have said for years that I thought leaf blowers were over rated but upon being confronted with such passion, I did a little homework and here is what I found:

1) On leaf blower noise: A blower measuring 70-75 dB at 50 feet can reach 90-100 dB at the operator’s ear. OSHA requires hearing protection for noise over 85, and Deafness caused by noise is irreversible. According to the American Academy of Otolaryngology, half the wearers of hearing protectors do not get the expected benefit, due to improper fit or failure to wear them continuously. According to Dr. Alice Suter, in a 1994 report to the OSHA Standards Planning Committee, there is recent evidence “that high levels of noise and the resulting hearing losses contribute to industrial accidents” and “hearing protection devices…may actually impair work safety under certain conditions…In addition, there is growing evidence that noise adversely affects general health, and the cardiovascular system in particular.”

2) On air pollution contributed by leaf blowers: Emissions from the two-stroke combustion engine include PM as well as gaseous carbon monoxide, nitrogen oxides, and hydrocarbons (CO, NOx, and HC). Leaf blowers also raise (entrain) dust from the ground. Leaf blower motors are inordinately large emitters of CO, NOx, HC, and PM. Two-stroke engine fuel is a gasoline-oil mixture, thus especially toxic. Particles from combustion are virtually all smaller than PM2.5. According to the Lung Association, a leaf blower causes as much smog as 17 cars. Finally, there is the damage to the plants and the soil itself, leaf blowers generate wnd speeds in excess of 180 mph, ripping leaves from branches, new growth and developing flowers are damaged and precious topsoil is blown away. Nurseries and Extension Agents are receiving more plant samples from gardeners indicating a tornado or hurricane devastated their landscape plants. In most instances the winds are unnatural in origin. Leaf blowers are producing wind speeds with greater force than a hurricane. They are having devastating effects.

3) Blower winds stress plants causing dehydration, burned leaves, and the suspension of photosynthesis and other natural plant functions. Overall growth is slowed. Natural openings in the leaves that allow for the exchange of oxygen and carbon dioxide are sealed shut. Disease spores laying dormant on the soil or fallen debris are blown back onto plants where a little moisture can renew their cycle of infestation and damage. The severity of damage corresponds to the training of leaf blower operators. Blowers effectively distribute disease spores, weed seeds and insect eggs throughout the landscape (as well as to neighboring landscapes). Blowers create a disposal problem for many landscape managers gathering up a tremendous amount of organic debris. Instead of utilizing it appropriately on site it is generally hauled away for disposal.

4) Another hidden cost of leaf blowers is that they deprive flowers, shrubs, and trees of life-giving mulch. Without this natural blanket, erosion, water evaporation and the spread of disease all become problems. Mulch, when not blown away, creates a favorable growing environment for plants and beneficial organisms both above and below ground while adding nutrients to the plants root zone. When mulch is removed to the compost and renewed annually many soil borne diseases are kept to a minimum.

In response to these issues, landscape professionals who use leaf blowers have stated that leaf blowers are great labor savers. However, several tests, including a public demonstration by Diane Wolfberg, a grandmother in her late fifties show otherwise

In three tests involving gas powered leaf blowers and battery powered leaf blowers, Diane cleaned the areas using rakes or brooms faster than any of the battery powered blowers and almost as fast as the gas powered leaf blowers and she did a better job in cleaning up the areas. For more information on leaf blower issues, the site where the bulk of the facts and some text on leaf blower risks was pulled from is:

http://www.nonoise.org/quietnet/cqs/leafblow.htm#6#6