by John Stewart
The research on links between mental health issues and noise is limited. So far no conclusive evidence has been found that noise causes mental health problems. But what the research has shown is that noise can exacerbate the problems; lead to depression; and that people with mental health issues are more likely to be annoyed by the noise in the first place.
It is worth stressing that, although I’m going to write about aircraft noise, researchers have found that the links between mental health and noise apply to all types of noise. It is likely, though, aircraft noise will be harder to deal with.
Given the political will, traffic noise – by far the most prevalent noise – can be cut. The Dutch researchers den Boer and Schroten (1) estimated that, with the right measures in place, it could be reduced by 70%. The biggest problem will remain main roads. Over the years, as side roads have been traffic-calmed and rat-runs closed, traffic has been shunted on to the main roads. And this has consequences for mental health. A recent German study (2) identified people ‘with a lower socio-economic status’ as particularly prone to mental health issues. And they live in disproportionately high numbers on busy roads. As far back as 1998, a study I carried out in the London Borough of Greenwich (3) found a fifth of council tenants rated traffic noise as big a problem as crime, with those living on main roads the most concerned.
Annoyance from wind farm noise is largely caused by the turbines being built too close to people’s homes. Many countries are now stipulating a distance of, typically, one or two miles away. But much depends on the terrain as the low-frequency noise produced by the turbines can carry a long distance and can penetrate walls in a way that higher frequencies generally don’t do.
Neighbour noise is a particular problem in low-income areas. A MORI survey (4) revealed that almost 20% of people with a household income of less than £17,500 (in 2003) regularly heard noise from neighbours, including 93% of social housing tenants. In contrast only 12% of people with an income of more than £30,000 could hear their neighbours. Neighbour noise can be dealt with through improved sound insulation and coming down hard on the noise makers.
So, although aircraft are not unique in causing noise problems that link to mental health, it might be uniquely difficult to come up with viable solutions. But before I explore solutions, it is worth looking at the research in more detail.
The most comprehensive piece of research is the NORA Study (5), carried out by the admirable Dirk Schreckenberg and his team in Germany. It found statistically clear connections for depression. The noise from airplanes, cars and trains increases the risk of suffering a depressive episode. The disease, which usually happens in episodes is one of the most frequent mental illnesses in Germany. Every fifth person experiences at least one depressive episode in his or her life. The causes of depression are frequent, but usually several factors come together. One possible factor is stress, which in turn may be caused by chronic traffic noise.
NORA found that an increase in noise levels increases the depression risk.
- by 8.9 percent in case of aviation noise.
- by 4.1 percent in road noise.
- by 3.9 percent in railway noise.
But then something unexpected happens. When the noise reaches a higher level, the risk of depression falls (see chart above): The rather unexpected results of the study included the results for depression at aviation and railway noise: The curve is an inverted U. This means: The risk for depressive disease increases with rising noise level first. In areas with very high aviation or railway noise exposure, however, the static risk drops again. The cause of this unusual distribution as compared to the other results cannot be determined by the NORAH study.
NORAH also found that changes in noise levels can be particularly unsettling: Changes in mental well-being follows changes in noise annoyance • The (indirect) relationship between sound levels and mental health is generally weak, but… gets stronger after the opening of the new runway in the group suffering from an increase in aircraft noise exposure after runway opening. • It seems that noise becomes relevant for mental health particularly when the noise situation worsens.
A second German study, from Beutal (2), found that aircraft noise can lead to depression and future mental stress. The five year longitudinal research, published this year, also found that mental distress may increase the vulnerability to noise (via heightened sensitivity to noise) in the first place.
We know when the general population is most likely to become disturbed by noise. I identified the key factors in my book (6): All of us, though, are likely to become more annoyed if we believe the noise may be harming our health or putting us in danger. We can get very annoyed too – even desperate – if we feel we have no control over the noise or we can’t stop it getting worse. We can be particularly disturbed when our neighbourhood suddenly becomes noisy – such as the introduction of a new flight path overhead. It is likely that these factors will be magnified for many people with mental health issues.
There is another important factor: the way anxiety levels can rise with the fears and rumours that the noise might become worse. As Chris Keady, who has bravely written about his mental health problems and to whom I am so grateful for first alerting me to the issue, wrote in a blog on the HACAN website: Talk of airport expansion and the possible prospect of more noise seriously raised my anxiety levels, and I knew from past experience that anxiety and worrying over intractable problems only sent me round in an endless loop, causing me to worry more.
So, if we know – and we are beginning to know – how aircraft noise can trigger mental health issues, what sort of solutions might work?
The NORAH Study identified one of them: periods of respite from the noise. It found that concentrated flight paths led to depression in some overflown people, and that respite was valued by those heavily overflown.
But I think we need to go beyond that, to what Chris Keady has called ‘Respite Plus’. This focuses much more on individual solutions for people with mental health issues. And this is where it gets a bit tricky. Everybody in the population will want the special treatment! There would need to be criteria that had to be met, such as proof from a doctor of mental health issues and an agreed minimum noise cut-off point. Then a plan would need to be drawn up in consultation with the resident. This would probably involve comprehensive insulation of the property with, in exceptional circumstances, agreement to buy the property. In the case of a tenant, it could mean assistance with moving away from the flight path.
When we have spoken with Heathrow about the whole issue of aircraft noise and mental health, there has been a commendable willingness to engage and to seek out solutions.
Whether or not a third runway is built – and, to ease the uncertainty for many with mental health issues, the sooner we get clarity from the Government on this, the better – the flight paths at Heathrow will see their biggest changes for decades. This is driven by the move from a ground-based system to a satellite one to guide planes in and out of the airport. Respite will be an integral part of the changes at Heathrow in a way that it is unlikely to be at many other airports. The package would be enhanced if Respite Plus was also included.
Heathrow has the chance to become a world leader in dealing with aircraft noise and mental health.
1. Traffic Reduction in Europe, den Boer and Schroten, published by CE Delft.
2. Gutenberg Health Study, Beutel et al
3. Poor Show, Stewart, published by ALARM UK/GASP
4. Mori Survey, commissioned by DEFRA
6. Why Noise Matters, Stewart et al, published by Earthscan