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 “A lot of work is done on air pollution and the public health
burden, but noise just never seems to get the same consideration,”
said senior author Richard L. Neitzel of the University of Michigan
School of Public Health in Ann Arbor.
High noise levels have been tied to poor health outcomes including
heart disease, possibly because sleep disturbances cause stress and
interrupt body cycles, he told Reuters Health by phone.
“These are crude estimates of what could be the savings if we
reduced exposures to this very common thing,” he said.
In 1974, the U.S. Environmental Protection Agency recommended an
average 24-hour exposure limit of 55 weighted decibels, with
nighttime noise weighted more heavily due to sleep disturbance, and
the agency last assessed exposure above those levels in 1981.
For the new estimate, the researchers assumed the proportion of the
U.S. population exposed to high levels of noise was the same in 2013
as estimated in 1981. Given that the country has further urbanized
over the last 30 years, that is likely an underestimate, Neitzel
said.
Nevertheless, he and his coauthors assumed 46.2 percent of
Americans, or 145.5 million, were exposed to at least 58 decibels
and 13.9 percent, or 43.8 million, were exposed to at least 65
decibels per day in 2013.
Using previous estimates, the researchers assumed that the risk of
hypertension or coronary heart disease increases by seven to 17
percent per 10 decibels of increased noise exposure.
Hypertension and cardiovascular disease account for 15 percent of
U.S. health expenditures, or about $324 billion per year. One-third
of U.S. adults have high blood pressure, according to the Centers
for Disease Control and Prevention.
As a result, the researchers suggest that reducing daily noise
levels by five decibels would reduce the number of people in the
U.S. with hypertension by 1.4 percent and those with coronary heart
disease by 1.8 percent. That would correspond to a savings of $3.9
billion annually, as reported in the American Journal of Preventive
Medicine.
“This again raises awareness that noise is actually a very important
exposure,” said Dr. Mathias Basner, assistant professor of Sleep and
Chronobiology in Psychiatry at the University of Pennsylvania
Perelman School of Medicine in Philadelphia.
“Most people know that if it is too loud that can damage your
hearing, but many people don’t know that noise has non-auditory
effects,” Basner, who was not involved in the new study, told
Reuters Health.
In addition to hearing damage and cardiovascular risk, high noise
levels may also have cognitive effects for children, he said.
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The newest available data in the U.S. are quite old, and things have
changed a lot in the American soundscape since the 1980’s, he noted.
Although cities have grown and individual noise events have
multiplied, the vehicles making the noise, like cars and planes,
have actually gotten quieter.
Not everyone in the U.S. is exposed to unhealthy levels of noise,
but some 100 million are, and the most common sources are automobile
traffic and aircraft traffic in dense cities, Neitzel said.
“Most of Western Europe is far ahead of the U.S. in understanding
people’s noise exposure,” he said. In the U.S. the most recent noise
exposure data we have is almost 40 years old, “whereas in Europe
they have requirements to map out and understand who’s exposed to
noise and have requirements to do something about it.”
“In the U.S. we just view it as a necessary byproduct of the
technology we use,” he said.
Neitzel hopes that these new rough economic estimates will draw more
attention to the problem of noise pollution.
A five-decibel reduction in noise would be quite significant,
equivalent to reducing vehicle traffic by about 75 percent, Basner
said.
People can reduce their noise exposures by making less noise, first
and foremost, as most noise disturbances come from things like
motorcycles and leafblowers, which don’t bother the user but do
bother passersby, he said. When arranging a house or apartment be
sure to situate your sleeping quarters away from any street exposure
the building may have, he said.
“Passive strategies, like new windows or insulation, can be very
effective for nocturnal noise exposure, but should really be our
last resort,” Basner said. “Noise that is not produced cannot have
effects.”
SOURCE: http://bit.ly/1M89HCN American Journal of Preventive
Medicine, online May 25, 2015.
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