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Civil Aviation Bill

My hon. Friend makes an important point, which other hon. Members have also raised. Different people have different noise thresholds, and that can also depend on whether they live close to the airport or further away. Flights come over my house, and I understand that this can be an issue. As I said a moment ago, research has suggested that the incidence of sleep disturbance is especially associated with the loudest noise events, and in particular those that produce more than a 90 dB sound exposure level. That measure expresses the level of a noise event as though all its energy were concentrated evenly in one second. It takes account of the duration of the sound and its intensity. A plot connecting points of equal sound exposure level from the departure or approach of a particular type of aircraft—or an envelope of the two—is known as a noise footprint. Hon. Members have already mentioned such footprints. The night noise insulation criterion that we have proposed as part of the consultation on night flying restrictions at Heathrow, Gatwick and Stansted airports relates to the 90 dB sound exposure level footprint of the noisiest aircraft operating at each airport. Such noise insulation seeks to mitigate the impact of each flight, as do the noise quota limits, by encouraging the use of quieter aircraft—[Interruption.] Does my hon. Friend the Member for Luton, North want to intervene on me?