在许多地铁站，通勤者暴露于峰值噪声水平，远远超过了可接受的水平。

Most of us who live in a large city would probably agree that our daily surroundings are noisy and are, annoyingly, a constant presence in our lives. But we might not all know that recent studies inmajor areas of the U.S.such as纽约, demonstrate how this type of noise poses a major public health risk. Growing evidence shows that hearing loss may lead to chronic health conditions such as hypertension or heart disease; it can lead to more aggressive behavior as well as increased stress and fatigue.

我们的研究小组通过对加拿大市政运输系统中的噪声暴露量进行采样，调查了长期噪声暴露对人的总体听力健康的影响，这是通勤者广泛使用的服务。使用个人噪声剂量计，我们系统地测量了不同运输方式的公共噪声水平：地铁，公共汽车和有轨电车平台，包括车载噪声。我们还为驾驶汽车，骑自行车或行走的通勤者测量了私人噪音水平。

在许多地铁站和运输车辆中，使用任何公共或私人运输方式的人暴露于峰值噪声水平，远远超过了可接受的水平。

我们的团队在多伦多进行了数百种测量，结果令人惊讶。我们发现，当考虑到平均通勤时间时，平均噪声暴露量在推荐水平之内。但是，在许多地铁站和运输车辆中，使用任何公共或私人运输方式的人们暴露于峰值噪声水平，远远超过了可接受的水平。

Why is this worrying?

Short loud bursts of noise can actually be more damaging to your hearing than long, softer durations of noise. This mechanism of damage is similar to that ofsoldiers或休闲猎人weaponry or combat noise. In most cases, our ears have a beautiful reflexive mechanism to help protect us from loud noise called the stapedial reflex, in which the smallest striated muscle in your body tenses up to stiffen up the little bones in the middle ear (ossicles) that transmit sound to our inner ear (cochlea). This stiffening dampens the amount of sound that enters our sensitive inner ear and protects the hair cells that convert sound energy to nerve impulses. However, the sudden nature of loud bursts of noise, such as the screeching of subway cars and buses, do not allow our ears enough time to deploy this protective mechanism, leading to permanent hearing loss.

Frustratingly, hearing loss affects 32 million children, but 60% of those children with hearing loss had preventable causes. This doesn’t take into account the 320+ million adults that are also affected by hearing loss, who are now more prone to a host of health issues such as depression, anxiety, and other degenerative conditions such as dementia.

Tackling noise pollution

Mass transit systems are a necessary part of every large metropolitan city worldwide, and this study aims to be an important reminder that city planners, engineers, and everyday citizens need to speak up and prioritize noise pollution as our public transit systems continue to expand in response to demand.

这项研究还强调了需要考虑我们日常生活的许多其他方面的噪音污染，例如道路噪音，娱乐活动和通过耳机和音乐设备的个人噪音暴露。有许多解决方案可以帮助减少噪声污染，但是直到我们将其作为一个主要的政策问题，它将继续被忽视：加剧影响我们长期听力和健康的危险。