Noise, or noise pollution, is defined as unwanted sound in the urban environment that causes discomfort, disturbance, or interference with living (Clark 2007; Mucci 2020). The increase in air and road travel means that more people are exposed to noise, and its effects are being recognised as an important environmental public health issue. The World Health Organisation (WHO) has estimated that at least one million healthy years of life are lost every year from traffic-related noise in western Europe, with sleep disturbance (903,000 disability-adjusted life-years lost) and annoyance (587,000 years) comprising the main burden (2011). In the literature, noise is measured using surveys, decibels, or audiometry tests.
Eight reviews examined the health impacts of noise exposure from over 380 primary studies (range 13-103 studies per review). Overall, exposure to noise had negative consequences on the rates of chronic diseases, childhood development, mental health, cognitive function, and physical health. One review found that reducing noise exposure was associated with improved mortality, birth outcomes, chronic diseases, and mental disorders (Salgado 2020).
Most (63%) reviews considered all age groups (three reviews did not specify age) and were conducted across the globe, with the majority in Europe (37%), North America (11%), and Asia (10%). One review solely focused on the health issues of road traffic noise in India (Banerjee 2012).
A strongly emerging theme was that noise pollution had a negative impact on cognitive performance in children’s education (Banerjee 2012; Clark 2007; Thompson 2022). A meta-analysis of three studies illustrated that children’s reading comprehension was greater in quiet classrooms than in high noise classrooms (Thompson 2022). Noise as a primary exposure had no association with either term birth weight or term low birth weight (Rugel 2020).
For chronic diseases, there was a significant risk of:
- hypertension (Banerjee 2012; Clark 2007; Mucci 2020; Thompson 2022),
- cardiovascular disease (Clark 2007; Mucci 2020; Rojas-Rueda 2021; Rugel 2020), and
- diabetes (Rojas-Rueda 2021).
A meta-analysis found that a rise of 5 decibels in aircraft noise was associated with a 25% increase in the risk of hypertension compared with those not exposed (Clark 2007). Another review found that each increment of 5 decibels of ambient noise was associated with an increased risk of hypertension (Rojas-Rueda 2021).
For mental health outcomes, exposure to noise was linked with:
- depression and psychological distress (Banerjee 2012; Clark 2007; Mucci 2020; Thompson 2022),
- anxiety (Clark 2007; Mucci 2020; Thompson 2022),
- stress (Banerjee 2012; Clark 2007),
- brain dysfunction (Mucci 2020),
- annoyance (Clark 2007; Mucci 2020)
- nervousness, agitation, and irritation (Banerjee 2012).
For physical health, noise pollution negatively impacted
- quality of life (Banerjee 2012; Mucci 2020),
- sleep (Banerjee 2012; Clark 2007; Mucci 2020),
- fatigue (Banerjee 2012),
- hearing, including auditory loss, tinnitus, speech inference (Banerjee 2012), and
- headaches (Banerjee 2012).
Although one review did not have sufficient evidence to draw firm conclusions (van den Bosch 2017), the majority of reviews found that noise exposure has a statistically significant negative effect on health and was associated with significant adverse effects. However, the mechanism and direction of causality between noise exposure and health outcomes are less clear as the relationship is complex, individual and environmental factors are rarely controlled for, and most primary studies were cross-sectional.
Noise exposure impacts some parts of the population more than others, including those working and living in industrial areas or places with higher volumes of construction, road traffic, rail, or airports. Thus solutions for these populations should be prioritised. Noise often co-occurs with air pollution, thus reducing the population’s exposure to noise will also positively impact rates of air pollution and the quality of the environment. Local and national governments should consider policies and multipronged solutions, including:
- supporting noise abatement procedures in schools and homes, including better insulation (Banerjee 2012; Clark 2007; Thompson 2022).
- incentivising transport, construction, and industry businesses to implement noise mitigation measures, such as avoiding school zones during the day and limiting nighttime operations (Thompson 2022).
- monitoring noise in cities and residential areas to keep levels below the WHO recommendation of 45 decibels, which has been found to improve nighttime sleep (Mucci 2020). The UK Department for Environment Food & Rural Affairs last updated its dataset maps of noise pollution in London in 2012.
- investing in prospective and longitudinal research studies (Clark 2007; Rojas-Rueda 2021; Thompson 2022) that involve cross-disciplinary teams, including researchers with specialities in health and urban planning.
The eight included reviews did not report any direct information on the cost or resource implications of noise exposures.
Quality of the evidence
There were two overviews of systematic reviews, four formal systematic reviews (one with a meta-analysis), one literature and one narrative review. Most reviews included cross-sectional studies, which limits the quality of the evidence as the sequence of exposure and health outcome is not as certain and factors such as socioeconomic status may confound the findings. Future research should design prospective and longitudinal studies to strengthen the quality of the evidence.
Searches for evidence were conducted between 2011 and 2020 in a median of four databases. The majority (75%) of reviews used a tool to assess the risk of bias or quality with one review of high quality, three of moderate quality, two of low quality and two of uncertain quality, giving the overall score of low-quality evidence.
The evidence was geographically generalisable as studies were conducted in various countries and contexts and represented most age groups across the population. However evidence gaps remain in Africa, Oceania, adolescents and young adult populations, an age group that may be at greater risk of adverse effects of noise.
Most reviews highlighted the limitation of heterogeneity in the methods and measures used for both the exposure to noise and health outcomes, making it difficult to combine and compare studies using meta-analyses. There were also variations in the definitions used and uncertainty of the source of noise exposures, the number of subjects exposed, length of exposure or the number of exposure events.
Improving the reporting and standardising of methods for future primary studies on noise exposure and health, where researchers apply the same measures for exposures, outcomes (e.g. ICD-10 codes), and statistical analyses, will enable direct comparison of findings and improve the quality of evidence.
External links to related sources
- Department for Environment Food & Rural Affairs (2012): Noise Pollution in London
- Department for Environment Food & Rural Affairs (2014): Environmental Noise – valuing impact on sleep disturbance, annoyance, hypertension, productivity and quiet
- WHO (1999): Guidelines for Community Noise
- WHO (2009): Night noise guidelines for Europe
- WHO (2011): Burden of disease from environmental noise – Quantification of healthy life years lost in Europe
- WHO (2018): Environmental Noise Guidelines for European Region
- European Environment Agency (2020): Chapter 11 Environmental Noise
- Policy Exchange (2021): Turning down the volume – Tackling noise pollution in the capital
References of included reviews
Banerjee D (2012) Research on road traffic noise and human health in India: review of literature from 1991 to current. Noise & health 14(58): 113–118.
Clark C and Stansfeld SA (2007) The effect of transportation noise on health and cognitive development: A review of recent evidence. International journal of comparative psychology / ISCP ; sponsored by the International Society for Comparative Psychology and the University of Calabria 20(2): 145–158.
Mucci N, Traversini V, Lorini C, et al. (2020) Urban Noise and Psychological Distress: A Systematic Review. International journal of environmental research and public health 17(18).
Rojas-Rueda D, Morales-Zamora E, Alsufyani WA, et al. (2021) Environmental Risk Factors and Health: An Umbrella Review of Meta-Analyses. International journal of environmental research and public health 18(2).
Rugel EJ and Brauer M (2020) Quiet, clean, green, and active: A Navigation Guide systematic review of the impacts of spatially correlated urban exposures on a range of physical health outcomes. Environmental research 185: 109388.
Salgado M, Madureira J, Mendes AS, et al. (2020) Environmental determinants of population health in urban settings. A systematic review. BMC public health 20(1): 853.
Thompson R, Smith RB, Bou Karim Y, et al. (2022) Noise pollution and human cognition: An updated systematic review and meta-analysis of recent evidence. Environment international 158: 106905.
van den Bosch M and Ode Sang Å (2017) Urban natural environments as nature-based solutions for improved public health – A systematic review of reviews. Environmental research 158: 373–384.