Even though the noise levels were within the recommended level of safe noise exposure, commuters were exposed to peak noise exposure which potentially can put commuters at risk of a noise-induced hearing loss, a Canadian study has found.
Noise levels in transportation
To exemplify how the noise levels of mass transit are harmful, the average noise levels for commuters in Toronto waiting on platforms for streetcars and buses or when cycling or walking to and from subways were examined. The study found that people biking were exposed to louder noise than people who were walking or driving a personal vehicle. The examination in the subway showed that commuters on the platforms were exposed to louder noise than commuters inside the subway carriage. In addition, the noise levels on subway platforms were louder than the noise level in personal vehicles.
When comparing public transport users and personal transport users, the study found that the loudest noise exposure for public transport users was at bus stops while users of personal transport where exposed to the loudest noise exposure when biking.
Peak noise exposure is harmful
The study found that the noise exposure in transportation was short and intense bursts of impulse noise. According to the American authority Environmental Protection Agency (EPA), an exposure longer than four seconds for a 114 dBA noise exposure and one second of 120 dBA noise exposure may result in greater risk of noise-induced hearing loss.
The peak noise levels in public transportation exceeded the exposure limit which has been found to be just as harmful as longer and less intense noise exposure.
“The average noise level is actually quite acceptable, but the concern is the peaks that people are exposed to,” said Dr. Vincent Lin, researcher of the study and associate professor in University of Toronto’s department of otolaryngology, Canada.
The measurements in subways showed that 20% of the measurements had a mean peak noise greater than 114 dBA, which exceeds the EPA noise thresholds guidelines. In addition, up to 85% of the measurements at bus stops exceeded the threshold by 54% greater than 120 dBA. Therefore, the study shows that commuters using mass transit are at risk of noise-induced hearing loss because the intense noise levels.
About the study
The study was carried out in the city of Toronto, Canada in April-August 2016 on mass transit including subways, buses, streetcars, private vehicles, cycling and walking. The noise levels were measured with a noise dosimeter attached to commuters’ shirt collars while they were using private and public transportation. All measurements were conducted on weekdays between 07:00 am to 07:00 pm in vehicles and on platforms. All in all, 210 measurements were conducted and compared to the EPA’s recommended thresholds to find out how harmful the noise thresholds were measured in dBA.
The study “Noise exposure while commuting in Toronto - a study of personal and public transportation in Toronto” was published in Journal of Otolaryngology – Head & Neck Surgery in November 2017.
Source: www.ncbi.nlm.nih.gov and Journal of Otolaryngology – Head & Neck Surgery