Noise: Much More Than a Nuisance

We are surrounded by noise—especially in cities—and yet we often overlook its importance. And it’s more than a mere nuisance: noise is a serious public health problem that has serious repercussions. Just how big is the impact of noise on our health? Let’s start with an example: a study carried out in Barcelona found that urban noise causes at least as much disease as air pollution in the city.

A study carried out in Barcelona found that urban noise causes at least as much disease as air pollution in the city

The World Health Organisation (WHO) recently published Environmental Noise Guidelines for the European Region, which include public-health recommendations on maximum levels of noise exposure. The guidelines establish different levels for different sources of environmental noise: transportation (aircraft, trains and road traffic), wind turbines and leisure activities.

Just as motor vehicles are inevitably a part of any discussion of air pollution, road traffic is the main source of noise pollution both inside and outside of cities. In fact, besides having their main source in common, air pollution and noise pollution share another attribute: in Europe, they are the two environmental factors that cause the most harm to our health, according to the WHO.

Road traffic is so ubiquitous that one in every five Europeans is exposed to high levels of noise (over 55 dB) from this source—100 million people in total. Of these, 32 million people are exposed to very high levels of traffic noise. The problem is even more serious in Spain, where an estimated 25% of the population is exposed to traffic noise levels higher than 55 dB on a daily basis. By way of comparison, the average daily traffic noise level recommended by the WHO is 53 dB.

Health Impacts of Noise

Exposure to noise can have direct and indirect health effects. Very high noise levels can damage hearing, causing tinnitus or even deafness. The noises we encounter in cities are not usually this loud, but exposure times can be long. The constant presence of unwanted noises is associated with stress, annoyance, sleep disorders, cognitive impairment and cardiovascular disease, particularly ischemic heart disease. Recent research has for the first time established links between traffic noise and an increased risk of diabetes and obesity, and ongoing research is looking into the possible effects of traffic noise on pregnancy.

The constant presence of unwanted noises is associated with stress, annoyance, sleep disorders, cognitive impairment and cardiovascular disease, particularly ischemic heart disease

One of the mechanisms that cause these health effects is stress. Annoyance caused by stress has a negative impact on quality of life and can even affect our behaviour. Noise-related stress can also lead to physiological reactions, such as hormonal imbalances and high blood pressure, which are even greater during sleep.

Night-time noise can lead to sleep disturbances, which can be harmful even if we are unaware of them and even if they are not loud enough to wake us up. Sleep disturbances are detrimental to health, since they can cause metabolic disturbances such as the interruption of glucose metabolism and the deregulation of appetite. Long-term exposure to noise may lead to chronic alterations in physiological reactions. These alterations could explain the associations, reported by several studies, between prolonged exposure to traffic noise and cardiovascular disease, diabetes and obesity.

Disease Burden in Europe

Data published by the European Environment Agency tell an interesting story: noise causes an estimated 16,600 premature deaths and 72,000 hospitalisations in Europe each year. Additionally, noise is a source of annoyance in an estimated 32 million people and causes sleep disorders in 13 million people.

A study carried out by the Barcelona Institute for Global Health (ISGlobal) concluded that air pollution and noise are responsible for 1,200 premature deaths in Barcelona each year. Another ISGlobal study estimated that 13% of Barcelona’s total burden of disease can be attributed to poor urban and transport planning. Of all the factors that contribute to this burden, noise is the most significant, accounting for 36% of the total. These estimates are based on current noise limits and could increase with the application of the new WHO Environmental Noise Guidelines, which establish lower recommended exposure thresholds for health safety.

To reduce the burden of disease from its current high level, the European Union has set the goal of decreasing noise pollution levels. The European Union noise directive requires all cities with more than 100,000 inhabitants to develop strategic maps of noise exposure levels associated with various sources and to implement action plans. The Barcelona provincial government has also drawn up strategic maps of traffic noise and action plans for the road networks under its control.

What Can Be Done?

Reducing noise is a collective task and local governments must play a leading role. Since traffic is the main source of noise, any measure designed to reduce traffic must have a positive impact on noise pollution. Other mitigation measures that should be considered include reducing speed limits and installing low-noise road surfaces.

In any case, the approach that offers the greatest benefits—and not just in terms of noise pollution—is shifting our cities towards a people-centred model. By prioritising public and active modes of transport and replacing public space currently reserved for motor vehicles with green spaces, cities can reduce noise levels and air pollution while also encouraging physical activity.

Our cityscapes should include quiet, pleasant spaces that promote well-being rather than increasing health risks. Urban and transport planning are key tools in achieving these goals.