The U.S. mass transit system, the largest in the world, provides affordable and efficient transportation to more than 33 million riders each weekday. The system is generally considered one of the safest modes of travel. But recent public health studies have identified several sources of environmental hazards associated with mass transit, including excessive noise, a large and growing problem in urban settings.
Now, a team of researchers from the University of Washington and Columbia University have found that Metropolitan Transit Authority (MTA) subways had the highest average noise levels of all mass transit in New York City, with levels high enough to potentially increase the risk of noise induced hearing loss. Researchers studied the risk of excessive exposure to noise related to mass transit ridership, and conducted an extensive set of noise measurements of New York City mass transit systems. Noise induced hearing loss, a permanent, irreversible health problem.
The scientists found that on average, the MTA subways had the highest noise levels, at 80.4 decibels (dBA), followed by the Path trains, at 79.4 dBA, and the tram, at 77.0 dBA. The lowest average levels measured, 74.9 dBA and 75.1 dBA. The very highest levels measured in the study were found on an MTA subway platform (102.1dBA) and at a bus stop (101.6 dBA).
In contrast, the noise level of a whisper is 30 dBA, normal conversation is 60 to 70 dBA, a chainsaw is 100 dBA, and gunfire is 140 dBA.
The scientists said that noise control efforts, including increased transit infrastructure maintenance and the use of quieter equipment should be a priority. What’s more, the use of personal protection will also be helpful. Music headphones and earbuds generally do little to reduce noise exposures, and in fact often increase exposures, as users turn the volume of MP3 players up even higher than normal to drown out surrounding noise. They recommend that most earplugs and earmuffs sold commercially would be sufficient to reduce transit noise exposures to below the recommended limits.
[Source]
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Chapter: Ear Care ::
24 August 2009
