Noise from listening to MP3 players and stereos has eclipsed the noise from loud work environments, even though it still is a small fraction of each person's total annual noise exposure.
Rick Neitzel, assistant professor at University of Michigan School of Public Health and Robyn Gershon, professor at University of California, San Francisco, found that one in 10 commuters had noise exposures exceeding the recommended limits from commuting alone.
But when they estimated the total annual exposure from all sources, 90 percent of commuters and 87 percent of non-commuters 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 said, according to a Michigan statement.
"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. The implications are startling," said Neitzel.
"Lots of people appear to be exposed at hazardous levels," he said. "A growing number of studies show noise causes stress, sleep disturbance, and heart disease."
They looked at what caused the majority of potentially harmful exposures in 4,500 residents in New York City who used public transportation.
The average New York commuter spends about 380 or so hours either waiting for or riding transit, which has average noise levels of 72-81 decibels.
For comparison, the average speaking level is 60 decibels, a busy street corner is 80, a circular saw is 90, a baby crying 115. The threshold for pain is about 125, and even a brief, one-time exposure above that level can cause permanent hearing loss.