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Dying for some quiet: The truth about noise pollution
22 August 2007
NewScientist.com news service
Andy Coghlan

Enlarge How noise damages health in Western Europe

Frank Parduski Senior could arguably qualify as the world's first anti-noise martyr. He died on 5 June in Lancaster county, Pennsylvania, while attempting to slow down a 19-year-old motorcyclist who had been speeding back and forth outside Parduski's house. On impact, the 82-year-old was thrown 10 metres and died at the scene from multiple injuries.

Parduski's death came as a result of his sheer frustration at being subjected to unwanted noise. However, alarming new evidence from the World Health Organization (WHO) suggests that thousands more people around the world may be dying prematurely or succumbing to disease through the more insidious effects of chronic noise exposure.

Though preliminary, the WHO's findings suggest that long-term exposure to traffic noise may account for 3 per cent of deaths from ischaemic heart disease in Europe - typically heart attacks. Given that 7 million people around the globe die each year from heart disease, that would put the toll from exposure to noise at around 210,000 deaths.

The WHO's investigations have been triggered in part by a rapid increase in complaints about noise pollution in recent years. For example, in May a survey by the UK's National Society for Clean Air (NSCA) showed that noise had a "major impact" for 45 per cent of respondents, compared with 35 per cent a year earlier. Meanwhile, figures collected by the UK Office for National Statistics suggest that noise complaints to local government offices have increased fivefold over the past 20 years. Noisy neighbours ranked high on the list of annoyances, as did pubs and clubs. Two per cent of respondents to the NSCA study said they had moved house because of noisy neighbours.

While excessive noise is certainly annoying, it has been unclear how this might translate into an actual impact on human health. Since 2003, the WHO's Working Group on the Noise Environmental Burden of Disease project has been attempting to address this problem. Using data from pioneering studies in countries including Germany, Switzerland and the Netherlands, a panel of international experts has met four times, most recently in December 2006, to agree preliminary estimates of the impact of noise on the entire European population (see "Estimating the effects of noise"). The objective is to develop a standard rationale by which individual countries can decide how much money to spend on noise reduction to improve health.

As well as the projections for deaths from heart disease, the new figures suggest that 2 per cent of Europeans suffer severely disturbed sleep because of noise pollution, and at least 15 per cent suffer severe annoyance. The researchers calculate that chronic exposure to loud traffic noise causes 3 per cent of all cases of tinnitus, in which sufferers hear constant noise in their ears. They also estimate the damage caused by noise pollution to children's ability to learn, and the damage to hearing caused by "leisure noise" such as listening to loud music on MP3 players or attending pop concerts and discos (see Table).

The most startling discovery, however, is the link with death. "The new data provide the link showing there are earlier deaths because of noise," says Deepak Prasher, professor of audiology at University College London, and a member of the coalition of European scientists who helped assemble and analyse the data. "Until now, noise has been the Cinderella form of pollution and people haven't been aware that it has an impact on their health," he says.

Quiet please

The new WHO estimates should provide governments with stronger justification for regulating sound, and help local authorities decide where to take action. By the end of this year, all European cities with populations exceeding 250,000 will be required by European law to have produced digitised noise maps showing hotspots where traffic noise and volume are greatest. Coupled with data on health effects, this should allow them to better target anti-noise measures, such as re-routing traffic away from hospitals and schools and erecting noise barriers.

Prasher and other members of the WHO working group hope that revealing the scale of the health impact will help jolt more dismissive governments around the world into taking action to regulate noise. In the US, for example, neither the government nor the Environmental Protection Agency (EPA) provide any resources for monitoring, regulating or researching noise. Everything is left to ad hoc action by states and cities.

New York is leading the way in this respect. On 1 July, mayor Michael Bloomberg introduced strict new laws to combat noise pollution, updating the city's 30-year-old noise code to take account of modern sources of noise such as loud stereos, car alarms and the spread of air conditioners. The change was implemented after the city received a record 354,378 complaints about noise in 2006, up 7 per cent from a year earlier.

Arline Bronzaft, a veteran noise researcher who chairs the noise committee of the Mayor of New York's Council on the Environment, believes that the campaign against loud noise is stepping up a gear in the US. "There are more and more anti-noise groups, and they're beginning to have an impact," she says.

Richard Tur, founder of NoiseOFF, an organisation lobbying against unwanted noise, agrees. "I think there's a groundswell movement against noise pollution in the US," he says. "But with the current administration, there's no chance of meaningful environmental legislation coming out of Washington. America has become a culture of noise."

John Millet, an EPA spokesman contacted by New Scientist, admits that there is a problem. The EPA used to have its own dedicated noise unit, called the Office of Noise Abatement and Control, but this was closed down during the early 1980s when anti-noise regulation was devolved to individual states and cities.

"We've always acknowledged that noise can exacerbate serious health problems over and beyond damage to hearing," says Millet. "It was clear to us in the 1980s and before that noise pollution was serious and raises stress levels, and causes a wider array of health issues including cardiovascular impacts, blood pressure, even heart attacks to those who were susceptible." However, "There isn't any funding for noise pollution at the US EPA," he adds.

Whether the new WHO data will change this remains to be seen. Bronzaft at least hopes it will be a start. As for Louis Hagler, a veteran campaigner against noise pollution in Oakland, California, he hopes that noise will eventually become as socially unacceptable as other forms of pollution, such as smoking. In a recent article condemning noise as a "modern plague", Hagler notes that "domestic tranquillity" is one of the six guarantees of the US Constitution (Southern Medical Journal, vol 100, p 287).

From issue 2618 of New Scientist magazine, 22 August 2007, page 6-9

Estimating the effects of noise Demonstrating that chronic exposure to noise can produce illness or death is not simple. For example, traffic generates air pollution at the same time as noise, so how do you separate out the effects of the two? The principle the WHO uses is the same one used to assess the effects of other environmental pollutants such as cigarette smoke or ozone. Find households with abnormally high exposure to noise, and compare death and disease rates in these households with those in quiet neighbourhoods. The WHO's researchers also studied groups of people with particular diseases, such as coronary heart disease, and tried to work out whether abnormally high exposure to noise increased their risk of dying. Finally, they combined this information with data from "sound maps" that highlight which parts of European cities are noisiest. Knowing the proportion of the population exposed, it was then possible to work out roughly how many people will die or suffer disease as a result of noise exposure, and to estimate the number of years of health that exposure to noise will wipe out (see Table). So how loud is loud noise? Sound exposure is generally measured in decibels (dB), which reflect the pressure on the eardrum. While the WHO has yet to finalise what levels of chronic exposure cause ailments such as heart disease and tinnitus (see Table), its Night Noise Guidelines for Europe can be used as a rough guide. These are due to be presented at the Inter-noise conference in Istanbul next week, and include threshold exposure levels that, if routinely breached at night, would threaten health. The threshold for cardiovascular problems, for example, is chronic night-time exposure of 50 dB or above. For sleep disturbance, the threshold is lower, at 42 dB, and lower still for general annoyance, at just 35 dB. The threshold of noise judged to have a negative impact on children's learning is 55 dB during night or day. That 55 dB is roughly equivalent to the din you would expect in a busy restaurant, while 75 dB is roughly equivalent to the noise at a busy junction such as Piccadilly Circus in London.

How noise causes illness How could exposure to noise have such devastating effects on human health as causing cardiovascular disease? Key to solving this puzzle is recognising that noise can create a form of chronic stress that keeps our bodies in a state of constant alert. Research published last year by Wolfgang Babisch of Germany's Federal Environmental Agency in Berlin shows that even when you are asleep, your ears, brain and body continue to react to sounds, raising levels of stress hormones such as cortisol, adrenalin and noradrenalin. This makes evolutionary sense, as all animals need to be alert to threats even when they are asleep, so they can wake up and flee if necessary, says Andy Moorhouse, an acoustics researcher at the University of Salford, UK. However, if these stress hormones are in constant circulation, they can cause long-term physiological changes that could be life-threatening. The end result can be anything from heart failure and strokes to high blood pressure and immune problems. "All this is happening imperceptibly, and this is the key," says Deepak Prasher of University College London, who collaborated on the WHO study. "Even when you think you're used to noise, these physiological changes are still happening," he says. What's more, there are a wide range of sources of noise stress. Some are big and obvious, such as constant heavy traffic or aircraft taking off, while others are much more subtle and difficult to define as "pollution", yet can still cause intense anxiety and irritation. In the case of noisy neighbours, for example, stress might be triggered simply by knowing a neighbour is in, even if they are not being noisy at that point. "If you have no control over the noise, that's what creates anger and stress and causes people to tip over the edge," says Val Wheedon, a veteran campaigner against noise pollution in the UK and co-founder of the UK Noise Association. In such disputes, noise serves not only as an irritation, but symbolises perceived lack of consideration in others, priming the body for confrontation, Wheedon adds. Noise can aggravate stress still further if it disturbs sleep, which can result in constant fatigue and outbursts of aggressiveness and irritability. People exposed to noise during their sleep have been shown to wake up more often and fidget more in their sleep - both indicators of sleep disruption. There is also mounting evidence that excessive noise disrupts learning and education. As far back as 1975, studies by Arline Bronzaft in New York showed that the reading skills of children in classrooms next to noisy railways lagged three to four months behind those of their peers in quieter classrooms. More recently, Staffan Hygge of the Laboratory of Applied Psychology in G�vle, Sweden, demonstrated that the long-term memory recall of children in part of Munich, Germany, improved by 25 per cent after a nearby airport was closed (Psychological Science, vol 13, p 469). The recall ability of children living near the new airport deteriorated by the same amount once it opened.

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