The effects of noise pollution

People in urban areas are often inundated by noise on an almost constant basis, to such a degree that many are not even aware of it any more — like other forms of pollution, it’s just ”in the air.”

But the ubiquity of noise does not make it benign: Noise pollution affects everyone, whether or not they’re conscious of or concerned by it.

As was the case with cigarette smoking in the 1960s and ’70s, the health effects of noise are not well understood by most people — including public officials — and are often dismissed as being of little concern. But noise is an increasingly prevalent issue that can have significant physical and social impacts on individuals, neighborhoods, and communities as a whole.

Those who ignore or downplay the salience of noise, and the growing efforts to reduce it, will be surprised how quickly it becomes a much broader public issue, much as smoking and drunk driving did after being tolerated for many years.

Health Effects

Like other types of pollution, exposure to noise can have major consequences for people’s health. Like other animals, evolution programmed the human body to respond to noise as a warning of a potential threat, and scientists theorize that modern sources of noise activate this natural ”flight or fight” response.

Numerous scientific studies have documented how exposure to noise triggers the release of stress hormones such as adrenaline and cortisol, which can raise people’s heart rates and blood pressure, even during sleep, and inhibit their immune systems. For this reason, noise pollution is considered a significant public health issue with a variety of adverse effects, including:

Cardiovascular disease — Evidence links ambient noise, and loud traffic in particular, to various cardiovascular effects including high blood pressure, hypertension, heart disease, and stroke. Some studies further suggest that night-time noise has an especially large impact, as the awakening response triggered by noisy environments takes a physiological toll over time.

Sleep disruption — Noise can have immediate effects on sleep such as waking people up or altering their sleep stage, next-day effects such as issues with cognitive functioning and productivity, and long-term effects such as chronic sleep problems and impaired immune systems. The World Health Organization (WHO) reports that night-time noise ”may reduce the restorative power of sleep” and that sleep fragmentation can impact motor performance and even creativity, among other things.

Cognitive impairment — An alarming amount of evidence connects noise with impaired cognitive development in children, whose developing brains are more susceptible to its disruptive effects. Repeated exposure to noise during critical periods of development may affect a child’s acquisition of speech and language, reading and listening skills, and problem-solving and memory.

One compelling study cited by the WHO found a link between noise exposure and deficits in memory and reading comprehension, which went away when the exposure ceased. For this reason, reducing noise levels around schools is a key focus for public policy.

Annoyance / anxiety — The WHO points out that getting annoyed at noise can itself have ”an adverse effect on health” and lead to a host of stress-related symptoms such as anxiety, fatigue, depression, and stomach ailments.

Hearing damage — Noise-Induced Hearing Loss (NIHL) is the most obvious and directly correlated effect of extended exposure to excessive noise, but research also points to it as a potential cause of tinnitus, a condition in which people hear a persistent hissing or ringing sound being generated inside their ears (which the WHO describes as ”the inability to perceive silence”).

Other reported effects include Type 2 diabetes, low birth-weight in babies, aggravating dementia in older adults, and even affecting patient outcomes and staff performance in hospitals. Conversely, studies show that reducing noise levels can help lower blood pressure, facilitate the development of new brain cells, decrease stress levels, and prevent plaque formation (arterialsclerosis) in arteries.

”[I]n every country, people’s health could be improved by reducing
environmental risks including pollution, hazards in the workplace,
[sun exposure], noise, … and climate and ecosystem change.”

— World Health Organization, 2007

Download our Health Effects of Noise infosheet in English and Spanish

Social Effects

Noise both reflects and affects the social fabric of neighborhoods and entire cities. It is among the most frequent quality-of-life issues cited by residents, and can often result in animosity and disputes between neighbors, sometimes with serious long-term consequences.

More broadly, noise is also an environmental justice issue, in that lower-income and “minority” neighborhoods are statistically more likely to be sites of noise-generating industries and municipal activities, and to expose inhabitants to higher levels of noise pollution than more socio-economically advantaged neighborhoods.

Living in louder neighborhoods accustoms residents to high noise levels as a baseline or “norm,” while in other parts of the city background noise levels are much lower. The constant din can make these areas feel chaotic and even anarchic, as the cacophony produced by a relatively small number of people can quickly overwhelm the quiet enjoyment of the majority who aren’t making noise.

In such an environment, some people come to believe that they’re entitled to make as much noise as they want, whenever they want, and that anyone who dares to object it is the problem, not them. This inversion of social responsibility undermines the whole idea of community, which is based on reciprocity.

For further discussion on the effects of noise, see the U.S. Environmental Protection Agency’s Noise Effects Handbook issued by the Office of Noise Abatement and Control in October 1979.