New study on effect of low ambient noise level on plane noise perception undermines Gatwick 2nd runway case
It is accepted that there is a difference in the way aircraft noise is perceived, depending on the level of background (ambient) noise. At its most obvious, someone standing near a noisy urban road will not notice the noise of a plane flying overhead as much as someone in a quiet location. GACC has commissioned work by Dutch noise experts, looking at the effect of ambient noise. The authors conclude that the % of annoyed residents is likely to be higher in areas with low ambient noise than in high ambient noise areas. The authors suggest that the number of people annoyed is likely to be higher than shown by Leq or Lden metrics, where local factors that influence annoyance are not taken into account. Gatwick is surrounded on 3 sides by designated tranquil areas such as the AONBs. GACC says that, with a 2nd runway, not only would three times as many people be affected by serious aircraft noise as now, but also – due to the effect of noise on quiet rural areas being under-estimated by the Airports Commission and by Gatwick – the usual comparisons between a large number of people annoyed by a new Heathrow runway and a smaller number at Gatwick are not valid. GACC say that, as well as a 3rd Heathrow runway, a 2nd Gatwick runway would also annoy a very large number of people. “Neither runway should be built.”
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New study undermines Gatwick’s second runway case
30.3.2016
By GACC – Gatwick Area Conservation Campaign
The Airports Commission stated that a new Gatwick runway would mean three times as many people as at present affected by serious aircraft noise. But it is worse than that
New GACC research study finds that the Commission, and Gatwick in their adverts, have underestimated the noise impact on rural communities that surround Gatwick: ‘The percentage of annoyed residents is likely to be higher in areas with low ambient noise than in high ambient noise areas’.
That means that the usual comparisons between a large number of people annoyed by a new Heathrow runway and a smaller number at Gatwick are not valid.
‘The failure by Gatwick to understand ambient noise explains why they were taken by surprise by the intense angry reaction to the new flight paths introduced in 2013-14’.
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According to the Airports Commission a second Gatwick runway would mean three times as many people as at present affected by serious aircraft noise. Many of them would, of course, be in Crawley: the proposed boundary of the new airport is only 100 metres from the residential areas. But the impact of aircraft noise would in addition stretch much further than previously recognised.
A new research paper, published by GACC today, shows that ambient noise – that is background noise – should be taken into account when assessing the impact of aircraft noise.
The first in a new series of research studies to be published by GACC is written by technical experts Ruud Ummels and Karin Elbers of the Dutch research agency To70.
Some key findings from the study:
The percentage of annoyed residents is likely to be higher in areas with low ambient noise than in high ambient noise areas.
It can be misleading to compare noise annoyance between different airports, when these local differences are not taken into account. Hence, the local difference between ambient noise levels should always be taken into account when calculating the annoyance.
As the level of ambient noise influences the perception of noise exposure, and therefore the subjective appraisal of noise annoyance, it is necessary to include ambient noise; especially when considering airport development or airspace changes. As the percentage of annoyed residents is likely to be higher in areas with low ambient noise than in high ambient noise areas, it can be suggested that the number of people annoyed is likely to be higher than shown by Leq or Lden metrics, where local factors that influence annoyance are not taken into account.
Brendon Sewill, GACC chairman, commented: ‘In quiet rural areas, and especially in designated tranquil areas such as the Areas of Outstanding Natural Beauty (AONB) which surround Gatwick on three sides, aircraft noise is likely to cause more annoyance, and annoy more people, than in busy urban areas.
‘This shows that the usual comparison between the large number of people affected by noise at Heathrow and the smaller number at Gatwick – much quoted by the Airports Commission and much used in Gatwick advertisements – is misleading.
‘The failure by Gatwick to understand ambient noise explains why they were taken by surprise by the intense angry reaction to the new flight paths introduced in 2013-14. People hate having their peace and quiet ruined and that is why so many new local protest groups sprang up, many of them ten or fifteen miles from the airport.’
The ambient noise study shows that more people are annoyed than shown by the official statistics. The phrase ‘local residents’ so well-used by journalists, now includes not only many of the 100,000 inhabitants of Crawley but also many living up to twenty miles from the airport.
‘GACC are not saying that these results prove that a new runway should be built at Heathrow. What they prove is that a second Gatwick runway would also annoy a very large number of people. Neither runway should be built.’
Sewill backs up his claim that a new runway is not necessary by drawing attention to the use of larger aircraft and the fact that Stansted will not be full until after 2040.
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See the “Ambient Noise research paper”
Contact Brendon Sewill, Chairman of GACC for further details– 01293 863369
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More GACC Research papers to come
GACC is preparing a number on research studies on the runway issue. They will be posted here when published.
The Ambient noise research study is the first to be published.
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