2 January 2012

Hazardous levels of noise exposure for 90% of city dwellers

by Will Parker

Nearly all city folk are exposed to sound levels that can cause permanent hearing loss, but University of Michigan researchers studying urban noise exposure were more surprised to learn that MP3 players, rather than noisy workplaces, were to blame.

"Noise from MP3 players and stereo use has eclipsed loud work environments, said Rick Neitzel, the principal investigator on the study. "This proved true even though MP3 player and stereo listening were just a small fraction of each person's total annual noise exposure."

Neitzel's study looked at 4,500 residents in New York City. He initially expected regular users of trains and buses along with work-related activities to be the chief culprits in excessive noise exposure. He found that one in 10 transit users had noise exposures exceeding the recommended limits from transit use alone. But when the subjects estimated their total annual exposure from all sources, 90 percent of transit users and 87 percent of nonusers exceeded the recommended limits, primarily due to MP3 and stereo usage.

"That two out of three people get the majority of noise exposure from music is pretty striking," Neitzel noted. "I've always viewed the workplace as a primary risk for noise exposure. But this would suggest that just focusing our efforts on the workplace isn't enough, since there's lots of noise exposure happening elsewhere."

Neitzel believes that the levels of exposure reported are a serious problem. "There aren't really any other experiences where we would tolerate having nine out of 10 people exposed at a level we know is hazardous. We certainly wouldn't tolerate this with another agent, such as something that caused cancer or chronic disease. Yet for some reason we do for noise."

Past studies have shown noise causes stress, sleep disturbance, and heart disease. "It may be the noise which we haven't historically paid much attention to is actually contributing to some of the top health problems in developed countries today," Neitzel suggests. "This begs for a public health education program."

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Source: University of Michigan