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General noise briefing

Noise is the major problem for most communities living around airports and under flight paths, especially at night.

The problem

Noise is the major problem for most communities living around airports and under flight paths, especially at night. Aircraft noise has been an issue ever since the introduction of the first jet aircraft, since when the benefits of progressive technological improvements have tended to be offset by the introduction of larger aircraft, more frequent movements (often at sensitive times of day) and growing community expectations.

The Government’s official noise index averages out the noise throughout the day: it measures the noise of each aircraft (i.e. the sound energy, in decibels, that each aircraft movement produces) and averages the total out over a 16 hour day to get what is known as an equivalent continuous noise level (abbreviated as LAeq).

This has been criticised on two counts. Firstly, the average includes the periods in the day when there are no aircraft noise events at some airports. This enables the government to claim that because there is no noise in some periods, the there is little or no nuisance at all.

Secondly, many people affected by noise know that, in assessing the noise, insufficient weight is given to the incidence of aircraft noise events. Because individual planes have got quieter over the last 20 years, the Government and industry can claim that noise exposure contours have shrunk and noise has reduced.

The reality is that noise remains as much of an issue today as it has ever been, if not more, as the number of noise events has substantially increased.The Government claims that “the onset of significant community annoyance” starts when the noise from aircraft averages out at 57 decibels, known as 57dB(A) LAeq.

The World Health Organisation (WHO) puts the figure between 50 and 55 decibels (and about 10 decibels lower at night). On this basis, it recommends maximum noise exposure levels of 55 dBA Leq to avoid the risk of people being significantly annoyed.

There is little prospect of significantly quieter planes being introduced over the next 20 years. The International Civil Aviation Organisation (ICAO) has set a tougher standard for new aircraft noise that will come into force until 1 January 2006.  However, the standard is already met by 98% of aircraft currently in-production. ICAO also agreed that there should be no global phase-out of existing “Chapter 3” aircraft to speed up the transition to quieter aircraft. This means that the sort of expansion envisaged in the Aviation White Paper will inevitably lead to more people across the country being exposed to higher levels of noise (a fact proven by the Government’s own noise calculations).

Looking to the future: Nobody – even within the aviation industry – claims that the level of expansion envisaged in the Aviation White Paper will not result in noise becoming a bigger problem for a greater number of people. The only way to avoid an increase in noise problems would be to reduce the number of aircraft movements, or to see a step-change in the noise of individual aircraft.

Neither is on the cards.The Government’s approach has been tacitly to accept that the noise climate will get worse and try to lessen the blow for those worst affected through the compensation and mitigation measures that airports are expected to provide. But these schemes are far from generous and are not on offer to the vast majority of people affected by aircraft noise.

European Action

The European Union published its Noise Directive in 2002. This requires member states to draw up noise maps (for ambient noise – aircraft, traffic, rail and construction sites) by 2007 and then produce action plans for dealing with the noise in the worst-affected areas by 2008.DEFRA takes the lead on this for the UK Government. It is behind schedule in drawing up its maps and plans.To a storm of criticism from those who want independent measuring and mapping, the aviation industry is heavily involved in drawing up the noise maps and action plans for airports.Unlike the Air Pollution Directive, the Noise Directive does not include targets to be met. But it will be revised after 2007. Campaigners are arguing that firm targets, with a timetable for implementation, should be included in a revised Directive.The other key document is the Charter on transport, environment and health which acknowledges the WHO guidelines on noise. Over 50 countries worldwide (including all EU countries) have signed up to these guidelines. The Aviation White Paper sees them as aspirational, maybe to be reached in 30 years time!Guidelines on Community Noise, by Berglund et al, published by the World Health Organisation (2000)Charter on transport, environment and health, World Health Organisation, 1999