Noise pollution and mental health

Writers in this journal have frequently discussed the effects of the environment on mental health (e.g. Callaghan et al., 2021; Cheng, 2021; Guha & Channon, 2020), and have occasionally noted the possible ill effects of atmospheric pollution (e.g. Guha, 2019). A surprising omission however, has been any discussion of the effects of noise pollution on mental health. The Journal of Mental Health is not alone in inadequately covering this topic. Hegewald et al. (2020) found recent evidence that “traffic noise may negatively impact mental health” but that “existing systematic reviews provide an incomplete overview.” Their meta-analysis showed that depression risk increased significantly with aircraft noise, but they “did not find enough studies to meta-analyze anxiety… and dementia/cognitive impairment and any traffic noise.” Similarly Clark et al. (2020) found that there was evidence that there was a “harmful effect of road traffic noise on medication use and on interview measures of depression and anxiety” but that “conclusions remain limited by the low number of studies.”

This dearth of relevant studies is surprising in that the World Health Organization (WHO REGIONAL Office for Europe, 2011) found traffic noise to be the second most damaging form of pollution to public health, after car exhausts. This could have been expected to have aroused more research interest. The situation is gradually changing however, with some clearer, more focussed projects.

A major national cohort study of adults in Denmark (Cantuaria et al., 2021) examined incident cases of all cause dementia and dementia subtypes, identified from national hospital registries. They found that a “ten-year mean exposure to road traffic… noises were associated with a higher risk of Alzheimer’s disease” and that there were “associations between road traffic and Parkinson’s disease related dementia,” summarising their findings as “transportation noise can be associated with a higher risk of all cause dementia and dementia subtypes, especially Alzheimer’s disease.”

The extent to which the effects of noise on mental health are omitted from research is irritating. There are many studies where noise pollution has simply not been taken into account. Thus, for example, Bravo-Moncayo et al. (2022) had found that people have a much clearer perception of the value of freedom from noise pollution than that from air pollution, and price their properties accordingly: rich people tend to live in quieter areas, so a US study finding that “Respondents reporting mental health difficulties… were more likely to be female, Hispanic or non-Hispanic black, have no more than a high school education, report lower incomes and less likely to be married” (Adepoju et al., 2018) might be significant in all sorts of ways, but one of them could well be that, in a very inegalitarian society, such people are more likely to be forced to live in noisy surroundings.

Similarly, a study of the benefits of exercise on mental health, such as Bergman et al. (2021) might have taken into account the fact that running, etc. tends to be organized in off-road situations which are likely to be quieter than the places where users spend most of their lives.

Children as an indicator species

A further restriction is that a considerable proportion of those studies that have been made seem to focus on adults. Gill (2021) rather unkindly, but probably accurately, suggests that newts and bats are legally required get more attention from urban planners in the UK than children do. He suggests that the presence and health of visible children is an indicator of urban health in the same way that the presence of salmon is an indicator of a healthy river. If children are rarely seen outside, are visibly obese or asthmatic, or if there is a high level of child mental disorder, this is an indication of an unhealthy urban environment.

Gill points out that “Traffic growth has transformed the domains of urban childhoods. Over the last 100 years traffic has emerged as a mortal threat to children who wish to get around their neighbourhoods… car-centric neighbourhood planning has only reinforced the logic of declining childhood freedoms and indoor sedentary lifestyles.” Parental concern tends to focus on traffic accidents, but Gill further points out that “The environmental threats children face include… air and noise pollution and poor mental and physical health. Their bodies are more vulnerable to pollutants of all kinds, and less well-equipped to cope… Noise pollution is a major environmental health problem with road traffic the dominant source… the effects of noise which go far beyond mere annoyance, mainly result from stress reactions….” Noise is more insidious and less dramatic than a road accident, and is therefore less likely to arouse attention.

In what is probably the first published assessment of the effect of traffic noise on cognitive development over time Foraster et al. (2022) studied children aged 7–10 in 38 different schools in Barcelona. They found that children in the schools in the noisiest zones had memory development over 20% lower and attention ability development 5% lower than those in the quietest areas. Their research further showed that peaks of noise audible in the classroom, such as loud lorries, police sirens or vehicles accelerating at speed from traffic lights had more impact than a high average level of noise. This matches the evidence base suggesting that children exposed to regular aircraft noise “have poorer performance on standardised achievement tests” (Basner et al., 2017). Previous research has tended to focus on average levels of noise, rather than sudden peaks.

It is obviously difficult to disentangle the effects of noise from those of atmospheric pollution, diet, night-time light, physical activity, over-crowded accommodation, etc., but there is a growing body of evidence suggesting that noise exposure weakens children’s cognitive abilities, and has some effect on the mental health of people of all ages.

What is to be done?

Most people today live in urban surroundings. The vast majority of the world’s children are brought up in urban areas in developing countries. Gupta et al. (2018) noted the adverse effects of noise in a North Indian city, in all age groups, including the foetus. Their suggestions include: “toys, personal, domestic, commercial, industrial equipment should be within the safe sound intensity. Loudspeakers and vehicular horns should be banned… Educational institutions, workplaces, commercial and industrial areas should be regularly monitored for noise levels… Traffic noise should be regulated… Bus-stands, railway stations and airports should be moved away from residential areas….” The chances of imposing such a regime on an Indian city seem extremely remote, but even in the relatively affluent UK, considerable campaigning in the face of a very vociferous motorists lobby would be needed to enforce low traffic areas surrounding all schools, to enforce urban speed limits and existing regulations on sounding horns in built-up areas, to increase safe, green, walkways between residential areas and shops, schools, etc., to ensure that wherever possible urban motorways are lined with acoustic screening, and to reroute air traffic away from urban areas, yet it is increasingly obvious that such changes are needed for the health of all of us, and of young children in particular.

Disclosure statement

My two local primary schools and my house are sited within earshot of both the Blackwall tunnel approach road and the proposed Silvertown tunnel approach road. They are also on the take-off path from London City Airport and on a direct route used regularly by low-flying twin-engined military helicopters from Woolwich barracks.