EarthTalk: Are my kids breathing in dangerous
exhaust fumes by riding the school bus?
-- Molly Schink, Winnetka, IL
24 million children ride the bus to school every day and
as a result are regularly exposed to harmful diesel exhaust
emissions. Major components of diesel exhaust include carbon
monoxide, sulphur dioxide, formaldehyde and tiny soot particles
that carry substances called polynuclear aromatic hydrocarbons.
U.S. Environmental Protection Agency (EPA) classifies diesel
emissions as a “likely carcinogen.” Diesel emissions
are estimated to be responsible for 70 percent of the cancer
risk arising from air pollution, according to the California
Air Resources Board. Dangers from diesel exhaust can range
from respiratory illnesses including asthma and bronchitis
to lung cancer and heart disease.
are more vulnerable to the effects of diesel exhaust than
adults because they breathe more quickly and take more air
into their developing lungs. And on average, school children
who ride the bus spend an average of 90 minutes each weekday
EPA estimates that approximately 390,000 diesel school buses
are on the road in the U.S. today. A third of these were
made before 1990 when stricter emissions guidelines were
first enforced. According to the National Resources Defense
Council (NRDC), a child riding inside a school bus may be
exposed to as much as four times the amount of toxic diesel
fumes as someone riding in a car directly ahead of it.
the EPA pledged more than $1 million to a partnership called
the Northeast Diesel Collaborative, which is comprised of
eight different public and private entities working together
to improve emissions on thousands of school buses throughout
the northeastern U.S. Recipient groups are using the money
primarily to reduce emissions on older buses by installing
advanced pollution controls.
old buses with such controls involves installing emissions
reducing filters. Diesel particulate filters, which cost
around $700 each, can cut tailpipe emissions by a whopping
85 percent. And “closed crankcase filtration systems,”
which are installed under the hood and filter the discharges
that come directly from the engine’s crankcase vent,
can cut engine soot by nearly 90 percent at a cost of around
$7,500 each. Buses can be retrofitted with one or both filters.
a number of school bus emission-reduction programs are underway
with the help of the EPA’s Clean School Bus USA program.
In addition to retrofit projects the program seeks to replace
older buses with new less polluting buses and encourage
unnecessary school bus idling.
parents can help reduce their children’s expose to
diesel emissions from school buses by advocating at town
and boards of education meetings for the use of new or retrofitted
school buses. Also, bus windows should remain open when
weather allows, and children are safer sitting nearer the
front of the bus, as exhaust tends to accumulate in the
Clean School Bus USA; Northeast
Diesel Collaborative; NRDC.
EarthTalk: What is “light pollution?”
Is it really a factor in breast cancer?
-- Gudrun Smythe, Madison, Wisconsin
The glow of city
lights blotting out stars in the night sky has frustrated
many a stargazer, but recent studies have shown that “light
pollution”--defined as excess or obtrusive light at
night--can actually have serious health effects. Researchers
have found that exposure to bright nocturnal light can decrease
the human body’s production of melatonin, a hormone
secreted at night that regulates our sleep-wake cycles.
And decreased melatonin production has in turn been linked
to higher rates of breast cancer in women.
at night is now clearly a risk factor for breast cancer,”
says David Blask, a researcher at the Cooperstown, New York-based
Mary Imogene Bassett Research Institute. “Breast tumors
are awake during the day, and melatonin puts them to sleep
at night,” he adds.
Richard Stevens of the U.S. Department of Energy’s
Pacific Northwest National Laboratory first discovered the
link between breast cancer and light pollution in the late
1980s. Stevens found that breast cancer rates were significantly
higher in industrialized countries, where nighttime lighting
is prevalent, than in developing regions.
to Stevens’ research are the findings of another researcher,
William Hrushesky of the South Carolina-based Dorn Veterans
Affairs Medical Center, who discovered that female night
shift workers have a 50 percent greater risk of developing
breast cancer than other working women. He also found that
blind women have high melatonin concentrations and unusually
low rates of breast cancer.
To reduce breast
cancer risks from light pollution, Prevention magazine recommends
nine hours of sleep nightly in a dark room devoid of both
interior (computer screens) and exterior (street lamps)
light sources. A study of 12,000 Finnish women found that
those who slept nine hours nightly had less than one-third
the risk of developing a breast tumor than those who slept
only seven or eight hours. Even bright light from a trip
to the bathroom can have an affect, so dim nightlights are
recommended for night lighting.
causes other problems besides increased cancer risks. According
to the Sierra Club, birds and animals can be confused by
artificial lighting, leading them away from familiar foraging
areas and disrupting their breeding cycles. And the photosynthetic
cycles of deciduous trees (those that shed their leaves
in the fall) have been shown to be disrupted due to the
preponderance of artificial nighttime lights.
Another environmental impact of excessive use of artificial
light is, of course, energy waste. The International Dark-Sky
Association computes that unnecessary nighttime lighting
wastes upwards of $1.5 billion in electricity costs around
the world each year while accounting for the release of
more than 12 million tons of carbon dioxide, the leading
greenhouse gas, into the atmosphere. Individuals can do
their part by keeping lights dim or off at home at night—and
convincing their employers and local government offices
to do the same.
Dark-Sky Association; New
York Sierra Club.