Aviation and noise

Noise is the pollutant which disturbs more people in their daily lives than any other. Yet it is often dismissed as no more than a local problem, even by the green movement. Noise consistently tops the list of complaints to New York’s helpline. In Europe, 450 million people, 65% of the total population, are exposed daily to noise levels which the World Health Organization (WHO) regards as unacceptable. Some local problem!

Across the world millions of people are disturbed by aircraft noise. At London’s Heathrow airport alone, it is estimated to approach 1 million people. The aviation industry will argue that individual aircraft have become a lot quieter over the past 30 years. This is true but the improvement has been off-set by the huge increase in the number of planes using airports.

Although the greatest numbers of people are exposed to traffic noise, there is evidence to show that people become disturbed more quickly by aircraft noise. The debate as to why people can get so disturbed by aircraft noise is ongoing but it could be to do with the high level of low-frequency content it contains. Wherever noise has a stronger than average low-frequency component – such as powerful stereo systems, wind turbines, and heavy trucks – it seems to become particularly problematic.

Flawed method of measuring aircraft noise

One Concorde followed by three hours and 58 minutes of relief was said to be as disturbing as four hour’s worth of non-stop noise from Boeing 757s at a rate of one every two minutes. Clearly not a reflection of reality!”

The level of disturbance is under-estimated by the way aircraft noise is usually measured. There are two major flaws.

The noise is averaged out over a given period. This method might work for a busy main road where traffic is fairly constant throughout the day but an average it is really not suitable for the more intermittent nature of aircraft noise. The averaging out of the noise includes the quiet periods of the day and the quiet days of the year, so underestimates the noise people actually hear. Moreover, the method of calculating the average gives too much weight to the noise of each plane and not sufficient to the number of planes – and so does not allow it to fully capture the main complaint of most residents: the huge increase in the number of planes there has been in the last couple of decades at most airports. A report published by HACAN, the organization that represents residents under the Heathrow flight paths, calculated that, by averaging out noise, one Concorde followed by three hours and 58 minutes of relief was said to be as disturbing as four hour’s worth of non-stop noise from Boeing 757s at a rate of one every two minutes. Clearly not a reflection of reality!

The other big problem with the measurement of aircraft noise is that the techniques used do not fully capture the low-frequency content of the noise. This is because ‘A’ weighting, rather than ‘C’ weighting, is used to measure the noise. The World Health Organisation suggests that, if the difference between ‘A’ weighted and ‘C’ weighted results is more than 10dB, the use of ‘C’ weighting should be considered when taking the results. There is a considerable amount of low-frequency in aircraft noise. When HACAN measured noise in West London, a few miles from Heathrow Airport, the difference between the ‘A’ weighted and ‘C’ weighted measurements was 9dB.

Technical solutions limited

There are few technical solutions which can improve the situation significantly. Electric or hybrid cars will cut the noise from cars. Not an option for planes! The aviation industry admits that there is no prospect on the horizon of noticeably quieter aircraft. Technology has a much greater chance of reducing emissions. Improved flight techniques could reduce the noise but governments need to face up to the fact that, if they are to improve the noise climate for millions of people, there will be little option but to cut the number of aircraft in the skies. That requires providing fast, affordable trains where rail is a viable alternative. It also requires investment in technology to allow for high-quality video-conferencing facilities and giving tax-breaks to firms who use them. Finally, it means ending the tax-breaks the aviation industry currently enjoys, such as tax-free fuel. These tax-breaks simply artificially create a higher demand for air travel.

Noise as an environmental justice issue

While all noise, including aircraft noise, can and does affect rich and poor alike, it is poorer communities across the globe that are most exposed to it and, as a rule, have the least opportunity to do anything about it. There is no double-glazing in the shanty towns. In my forthcoming book, Why Noise Matters I write: “There is an obvious question of social justice in what is happening. The high noise levels in many poor areas are caused, at least in part, by the activities of much wealthier people. Poor people have no cars to drive on the roaring new motorways that cut an ugly swathe through their fragile communities. The congestion on the city streets is not of their making. The flash new airports are not for them. They are the victims of other people’s lifestyles. Never were the words of Les Blomberg, executive director of the Noise Pollution Clearing House, more appropriate: ‘Second hand noise is increasingly used to describe noise that is experienced by people who did not produce it. Like second hand smoke, it’s put into the environment without people’s consent and then has effects on them that they don’t have any control over’.”



  1. Pingback: Transition Heathrow » Blog Archive - September 9, 2011

%d bloggers like this: