Noise pollution: learn about its consequences, how to measure it and how to avoid it

Vehicle congestion, pedestrian traffic, construction work in cities… all of these activities have a common pollutant: noise.

Despite the fact that noise pollution has a tremendous impact on human health and ecosystems, it is still not included in the list of air pollutants that require urgent attention.

Noise pollution is a real problem that affects almost all urbanised areas of the planet: excessive and persistent noise affects physical and mental well-being, alters quality of life and has negative effects on wildlife and the environment.

What is noise pollution?

According to Law 37/2003, the current noise legislation in Spain, noise pollution is defined as ‘the presence in the environment of noise or vibrations, regardless of the acoustic source that causes them, which cause discomfort, risk or damage to people, to the performance of their activities or to property of any kind, or which have significant effects on the environment’.

In other words, it is the presence of unwanted or harmful noise that interferes with human and animal activities.

The World Health Organisation (WHO) recommends not to exceed 65 dB during the day and 55 dB at night, although these limits are exceeded in most cities.

What are the health consequences of noise pollution?

Noise is a pollutant that cannot be seen, but it is experienced every day and can have both immediate and chronic consequences.

In addition to hearing loss and tinnitus, noise pollution also causes other non-auditory problems such as high sleep disturbance, insomnia, anxiety, stress, mental fatigue and irritability.

In fact, it goes even further: according to the European Environment Agency (EEA), ‘environmental noise causes around 12.000 prepature deaths per year in Europe and contributes to more than 48.000 new cases of eschaemic heart disease’.

Several studies have demonstrated the following consequences associated with continuous exposure to nois levels above the recommended limits:

• Sleep disorders, insomnia or difficulty resting properly.
• Stress, anxiety, irritability and chronic fatigue.
• Cardiovascular problems such as hypertension, heart attacks or strokes.
• Impaired cognitive performance, especially in children.
• Higher rate of premature deaths.

Studies have shown that repeated sleep disruption due to noise causes changes in blood pressure and heart rate, vasoconstriction, changes in breathing and increased body movements.

But it doesn’t just cause sleep disorders; noise also affects cardiac and cerebrovascular function, as suggested by preliminary research presented at the American Heart Association’s Scientific Sessions 2018 in Chicago.

According to the scientific team responsible for the study, noise stimulates activity in a region of the brain involved in the stress response, which causes inflammation of the blood vessels and can increase the risk of heart attacks and strokes.

Which population groups are most affected by noise?

Considering the different population groups, those most likely to be harmed by noise and therefore requiring maximum protection are pregnant women, foetuses, newborns, babies and children.

For example, prolonged exposure to loud sounds in pregnant women and children can cause temporary or permanent hearing loss, depending on the volume and duration of exposure. The younger the child exposed to noise, the earlier they will suffer from noise-induced hearing loss (NIHL) and other non-auditory problems.

The data supports this problem, as a series of audiometric tests carried out in the United States between 1988 and 1994 on 6,100 children and adolescents aged between 6 and 19 confirmed that approximately 15% had hearing loss in one or both ears.

Effects of noise pollution on the environment

But noise does not only affect people. Numerous animal species depend on sound to communicate, move around, avoid danger or find food, and their patterns are disrupted by noise pollution.

Studies such as those conducted by the FHWA in 2017 and by Martín and Grijota warn of the deterioration of natural habitats, especially in protected areas near transport infrastructure or urbanised areas, causing the following effects:

• Difficulty in perceiving acoustic signals and reduced responsiveness.
• Changes in foraging and anti-predator behaviour.
• Effects on reproduction.
• Impact on the density and structure of animal communities.
• Alterations in vocalisation and acoustic masking.
• Destruction and fragmentation of habitats.
• Modification of warning functions

Unfortunately, no member of the animal kingdom escapes the consequences of noise pollution: noise affects important pollinating invertebrates such as bees, which become paralysed at noise levels between 107-120 dB (a busy street, for example), and some species of forest birds, which have seen their population density reduced in areas adjacent to roads.

How to measure noise pollution

As explained in this other article, noise is measured using devices called sound level meters, which record levels in decibels (dB) weighted to reflect the sensitivity of the human ear.

The data obtained using these devices is used to produce acoustic studies, also known as noise maps, which are usually commissioned by public administrations and used to identify areas of conflict and define action plans.

Thanks to this, we now know that more than 100 million Europeans are exposed to noise levels above 55 dB, according to information provided by the European Environment Agency.

In cities and industrial environments, continuous noise monitoring systems such as those offered by ENVIRA enable compliance with legislation and protect both workers and the surrounding population.

How can noise pollution be prevented? Resources and legal rights

Preventing noise pollution requires action on three fonts: technical prevention, public awareness and use of available legal mechanisms.

At the individual and collective level, there are various effetive measures to protect against noise and report ir when it exceeds legal limits.

Measures to reduce noise in urban and industrial environments

Among the technical and urban measures that can be implemented by public authorities, it is important to have acoustic urban planning that considers the use of sound-absorbing materials in buildings, noise barriers in infrastructure, and the design of streets with vegetation barriers to dampen the effects of noise pollution.

It is also important to focus on traffic control, pedestrianising areas or restricting access to vehicles or construction sites at certain times, as well as regulating the hours of noisy activities and entertainment venues. In work and industrial environments, it is important to respect noise exposure limits and the mandatory use of hearing protection PPE.