Nov 2017 scimex
Rattling train carriages, honking cars and squealing breaks may do more harm than simply grinding your gears, as new research from Canada suggests that the noise levels bikers and public transport commuters experience could induce hearing loss. 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. Until this can be factored in by city planners, the researchers suggest you should cover your ears with appropriate protection.
Efforts to control noise should focus on materials and equipment that provide a quieter environment, researchers at the University of Toronto suggest. Hearing protection while using public transport should also be promoted.
Dr. Vincent Lin 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. Planners need to be more considerate of noise exposure in future planning of public spaces and public transit routes.
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. 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 117dBA for longer than two seconds and exposure to 120 dBA for longer than 20 seconds 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. 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 caution that the number of measurements taken for individual modes of transport is relatively low and that the cross-sectional nature of the study does not allow for conclusions about cause and effect. Further studies are needed to investigate other factors that may contribute to noise exposure such as use of music players and lengthy transit times.