Autumn leaf burning and Solar hot water heaters

EARTH TALK
From the Editors of E/The Environmental Magazine

Dear EarthTalk: Now that autumn is here the leaves are going to pile up in
my yard again. Is it really that bad to burn them? Why is it illegal to burn
leaves in so many places now?
-- Jeffrey Edwards, Westport, CT
Burning fallen leaves used to be standard practice across North America, but
most municipalities now ban or discourage the incendiary practice due to the air
pollution it causes. The good news is that many towns and cities now offer
curbside pickup of leaves and other yard waste, which they then turn into compost
for park maintenance or for sale commercially. And there are other burn-free
options as well.

Because of the moisture that is usually trapped within leaves, they tend to burn
slowly and thus generate large amounts of airborne particulates--fine bits of dust,
soot and other solid materials. According to Wisconsin’s Department of Natural
Resources, these particulates can reach deep into lung tissue and cause
coughing, wheezing, chest pain, shortness of breath and sometimes long-term
respiratory problems.

Leaf smoke may also contain hazardous chemicals such as carbon monoxide,
which can bind with the hemoglobin in the bloodstream and reduce the amount of
oxygen in the blood and lungs accordingly. Another noxious chemical commonly
present in leaf smoke is benzo(a)pyrene, which has been shown to cause cancer
in animals and is believed to be a major factor in lung cancer caused by cigarette
smoke. And while breathing in leaf smoke can irritate the eyes, nose and throat of
healthy adults, it can really wreak havoc on small children, the elderly and people
with asthma or other lung or heart diseases.

Sporadic individual leaf fires usually don't cause any major pollution, but multiple
fires in one geographic area can cause concentrations of air pollutants that
exceed federal air quality standards. According to the U.S. Environmental
Protection Agency (EPA), several leaf and yard waste fires burning
simultaneously in a particular locale can cause air pollution rivaling that from
factories, motor vehicles and lawn equipment.

Purdue University consumer horticulture specialist Rosie Lerner says that
composting leaves is the most eco-friendly alternative to burning. Dry leaves alone
will take a long time to break down, she says, but mixing in green plant materials,
such as grass trimmings, will speed up the process. Sources of nitrogen, such as
livestock manure or commercial fertilizer, will also help. “Mix the pile occasionally
to keep a good supply of air in the compost,” she says, adding that a compost
pile should be a minimum of three cubic feet and will generate soil conditioner
within weeks or a few months, depending on conditions.

Another option is to shred leaves for use as mulch for your lawn or to help protect
garden and landscape plants. Lerner suggests adding no more than a two-to-
three-inch layer of leaves around actively growing plants, chopping or shredding
the leaves first so they don’t matt down and prevent air from reaching roots.

As to using leaves as mulch for your lawn, it is just a simple matter of mowing
right over the leaves with the lawnmower and leaving them there. As with leaves
used for garden mulch, this will provide many benefits, including weed
suppression, moisture conservation and moderation of soil temperature.

CONTACTS: U.S. EPA Residential Leaf Burning Facts, http://es.epa.
gov/techinfo/facts/leafburn.html; “Composting for Beginners,” www.plowhearth.
com/magazine/compost_how_to.asp.

EARTH TALK
From the Editors of E/The Environmental Magazine

Dear EarthTalk: I heard that using a solar powered water heater in my home
would reduce my CO2 emissions significantly. Is this true? And what are
the costs? -- Anthony Gerst, Wapello, IA

According to mechanical engineers at the University of Wisconsin’s Solar Energy
Laboratory, an average four-person household with an electric water heater
needs about 6,400 kilowatt hours of electricity per year to heat their water.
Assuming the electricity is generated by a typical power plant with an efficiency of
around 30 percent, it means that the average electric water heater is responsible
for about eight tons of carbon dioxide (CO2) annually, which is almost double that
emitted by a typical modern automobile.

The same family of four using either a natural gas or oil-fired water heater will
contribute about two tons of CO2 emissions annually in heating their water.

Surprising as it may seem, analysts believe that the annual total CO2 produced by
residential water heaters throughout North America is roughly equal to that
produced by all of the cars and light trucks driving around the continent. Another
way of looking at it is: If half of all households used solar water heaters, the
reduction in CO2 emissions would be the same as doubling the fuel-efficiency of
all cars.

And that might not be such a tall order. According to the Environmental and
Energy Study Institute (EESI), there are 1.5 million solar water heaters already in
use in U.S. homes and businesses. Systems can work in any climate and EESI
estimates that 40 percent of all U.S. homes have sufficient access to sunlight such
that 29 million additional solar heaters could be installed right now.

Another great reason to make the switch is a financial one. According to the
EESI, residential solar water heating systems cost between $1,500 and $3,500
compared to $150 to $450 for electric and gas heaters. With savings in electricity
or natural gas, solar water heaters pay for themselves within four to eight years.
They last between 15 and 40 years--the same as conventional systems--so after
that initial payback period is up, zero energy cost essentially means having free
hot water for years to come.

What’s more, in 2005 the U.S. began offering homeowners tax credits of up to 30
percent (capped at $2,000) of the cost of installing a solar water heater. The
credit is not available for swimming pool or hot tub heaters, and the system must
be certified by the Solar Rating and Certification Corporation.

According to the U.S. Department of Energy’s “Consumer’s Guide to Renewable
Energy and Energy Efficiency,” zoning and building codes relating to the
installation of solar water heaters usually reside at the local level, so consumers
should be sure to research the standards for their own communities and hire a
certified installer familiar with local requirements. Homeowners beware: Most
municipalities require a building permit for the installation of a solar hot water
heater onto an existing house.

For Canadians looking to get into solar water heating, the Canadian Solar
Industries Association maintains a list of certified solar water heater installers,
and Natural Resources Canada makes its informative booklet “Solar Water
Heating Systems: A Buyer’s Guide” available as a free download on their website.

CONTACTS: U.S. Department of Energy, www.eere.energy.gov/consumer/;
Natural Resources Canada, www.canren.gc.
ca/app/filerepository/AC5201041AFA42A1BFD51EA128F787CF.pdf.

GOT AN ENVIRONMENTAL QUESTION? Send it to: EarthTalk, c/o E/The
Environmental Magazine, P.O. Box 5098, Westport, CT 06881; submit it at: www.
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past columns at: www.emagazine.com/earthtalk/archives.php.