Last updated February 23, 2018 at 3:51 pm
Rattling train carriages, honking cars and squealing breaks may do more harm than simply grinding your gears. New research suggests that the noise levels bikers and public transport commuters experience could induce hearing loss in a study published in the open access Journal of Otolaryngology – Head & Neck Surgery.
With an increasing proportion of the population living in cities, mass transportation has been rapidly expanding to facilitate the demand, yet there is a concern that these transit methods have the potential to result in excessive exposure to noise, and subsequently noise-induced hearing loss. This is of particular concern to Australian residents as more than two-thirds live in a capital city, a similar demographic to Canada where the study was carried out.
Measuring the amount of noise commuters are exposed to in Toronto, the researchers were surprised to find some bursts of noise were loud enough to affect hearing if commuters were exposed to it repeatedly over a long period of time.
Researchers at the University of Toronto found that noise levels commuters are exposed to while using public transport or while biking, could induce hearing loss if experienced repeatedly and over long periods of time.
Dr. Vincent Lin, the corresponding author said, “This study is the first to look at and quantify the amount of noise people are exposed to during their daily commute. We now are starting to understand that chronic excessive noise exposure leads to significant systemic pathology, such as depression, anxiety, increased risk of chronic diseases and increased accident risk. Short, intense noise exposure has been demonstrated to be as injurious as longer, less intense noise exposure.”
“We were surprised at the overall average noise exposure commuters experience on a daily basis, especially the peak noise intensity not only on trains but also on buses.”
Measuring noise exposure on public (subways, trams and buses) and private (cars, bike, walking) transport in Toronto, the researchers found that while noise on average was within the recommended levels of safe exposure, bursts of loud noise on both public and private modes of transportation could still place individuals at risk of noise-induced hearing loss.
To measure noise exposure, the researchers used noise dosimeters, which they carried on their shirt collars about two inches away from their ears. The researchers’ measurements compared the noise on subways, buses, and trams, whilst driving a car, cycling, and walking.
Peak noise levels in dBa across both public and personal transport exceeded the EPA recommended thresholds. The average noise levels by bike were greater than any level caused by modes of public transit.
The authors found that 85 per cent of peak noise measurements from bus platforms were greater than 114 dBA, while 54 per cent were greater than 120 dBA. Meanwhile, all peak noise exposures while riding a bike exceeded 117 dBA, with 85% being greater than 120 dBA. According to thresholds recommended by the US Environmental Protection Agency (EPA), exposure to 114 A-weighted decibels (dBA) for longer than four seconds, exposure to 117 dBA for longer than two seconds, and exposure to 120 dBA for longer than 1 second may put people at risk of noise-induced hearing loss. A-weighted decibels express the relative loudness of sounds experienced by the human ear, taking into account that sensitivity to noise differs depending on noise frequency.
When the authors extrapolated the EPA-recommended noise thresholds for an average Toronto commuter who uses public transport, the recommended level of noise exposure was exceeded in 9 per cent of subway, 12 per cent of bus, and 14 per cent of biking measurements but not when using trams, cars or when walking.
So clearly it sounds like biking to work might not be the healthy option its meant to be – at least when it comes to hearing health. Until noise reduction can be factored in by city planners, the researchers suggest you should cover your ears with appropriate protection, or use trams, cars or the best of all worlds – try walking to work.