Noise

Noise exposure is typically assessed by determining a noise contour. This represents an area around an airport inside which noise levels exceed a given decibel (dB) threshold, as shown in Figure 1.6. This section provides trends in the total noise contour areas, and number of people inside the noise contours of 47 major European airports. These are based on the indicators of Lden 55 dB and Lnight 50 dB, as defined in the EU Environmental Noise Directive [6], and were derived using the STAPES airport noise model.

Complementary noise metrics assessed for this report include: the population exposed to aircraft noise events exceeding 70 dB during day and night; the noise-induced annoyance and sleep disturbance based on the latest exposure-response guidance; and the noise energy index computed annually for all flight operations at EU28+EFTA airports.

What are Lden and Lnight?
Lden is the sound pressure level averaged over the year for the day, evening and night time periods, with a +5 dB penalty for the evening and +10 dB for the night. Lnight is the sound pressure level averaged over the year for the night time period only.
Due to the nature of decibels, if the traffic doubles at an airport but the noise of each aircraft movement is reduced by 3 dB, then Lden and Lnight levels will be unchanged. Likewise, the new Airbus ‘A320neo’ aircraft are about 6 dB quieter than the older ‘A320ceo’ during take-off, and consequently four take-offs by an A320neo create similar Lden or Lnight levels as one take-off by an A320ceo.

New, quieter aircraft could help stabilise noise levels around major airports, but noise nuisance may spread to other airports

Average noise levels around airports are still close to what they were in 2005, but are on an upwards trend again since 2013. The total population residing inside the Lden 55 dB and Lnight 50 dB contours of the 47 major European airports were 2.58 and 0.98 million people respectively in 2017 (Figure 1.7, Table 1.2). This is 12% and 13% more than in 2005 for Lden and Lnight respectively, but 14% and 20% more than in 2014. However, some airports within the 47 have seen their Lden and Lnight contours reduced. The total noise energy in the EU28 and EFTA region follows flight counts closely (Figure 1.11) but was 5% lower in 2017 than in 2005, indicating that noise technology has managed to compensate for the increase in average aircraft size. The average noise energy per flight indeed went down by 14% over this period.

The latest World Health Organization Europe guidance [16] recommends to assess aircraft noise annoyance above Lden 45 dB and sleep disturbance above Lnight 40 dB. Using this guidance, it is estimated that around 3.2 million people were highly annoyed by aircraft noise, and 1.4 million suffered from high sleep disturbance in 2017 around the 47 major airports. The number of people exposed to more than 50 aircraft noise events exceeding 70 dB per day was estimated to be 1 million in 2017 for the same airports; this is 60% more than in 2005.

If the latest aircraft types now entering the fleet deliver their expected noise benefits, the total population exposed to Lden 55 dB and Lnight 50 dB noise levels around the 47 major airports could stabilise and even start to decrease by 2030. This forecast assumes that there will be no further airport expansion and no change in population around these airports. Furthermore, around 110 airports could handle more than 50,000 annual aircraft movements by 2040, compared to 82 airports in 2017, thereby affecting new populations.

What is the noise energy index?
When an aircraft flies to an airport, and later departs again, the area around an airport is exposed to a certain amount of noise energy. The ‘noise energy’ index uses certified aircraft noise data to calculate a proxy for the total noise energy received on the ground during an aircraft landing and take-off, irrespective of how the aircraft is operated. The individual noise energy from each flight operation is then summed at the European level.

 

Aircraft noise in context
While individual aircraft have become less noisy due to technological improvements, the growing amount of air traffic in Europe means that an important part of the population is still exposed to problematic noise levels. In the EU, aircraft noise is the third biggest source of noise exposure after road and rail traffic. The European Environment Agency has estimated that more than 4.1 million people were exposed to Lden levels above 55 dB from aircraft at 85 major airports (over 50,000 movements per year) in 2011, which accounted for 3.2% of the total population exposed to this noise level from all sources covered by the EU Environmental Noise Directive [4].