From April 2004 to March 2007 the DLR-Institute for Aerospace Medicine conducted a study concerning the effects of nocturnal traffic noise, especially the effects and the assessment of different categories of traffic noise (air, road, rail). On this account the study bears the name AIRORA (Studies on the Cumulative Effects of Air, Road and Rail Traffic Noise).
As part of the DLR/HGF-Projct “Quiet Air Traffic” between 1999 and 2003 dose-response-realtionships for the nocturnal strain of air traffic noise were acquired in the Study STRAIN. Recommendations and the bonus-malus-regulations are based upon the fact that air traffic noise is sensed as more disturbing compared to road and rail noise. It is not known whether the different disturbance reactions depend on the different sounds itself or on a differing exposure of the varied carriers. Furthermore it is not clear if psychological findings can be confirmed in a medical-physiological context.
The rating of the three carriers is conducted individually and separatedly so far, although many people are exposed to several categories of traffic noise. Studies concerning the cumulative effects of multiple carriers are requiered urgently, for example for the design of the new European noise directive, but they are virtually non-existent at the moment.
The status of air traffic noise compared to the other carriers ought to be checked in three representative laboratory studies regarding the psychological and especially medical-physiological effects on human’s sleep out of this reason. It shall be clarified additionally, to which extent cumulative effects of different categories of traffic noise on the sleep of humans should be or have to be considered in corresponding legal regulations.
One phase of the study consisted of 11 consecutive research nights. Each of it started on a Monday evening and ended on Friday morning, the following week. Daytime activities were not regulated.
The study AIRORA is part of the DLR-Project “Silent Air Traffic II”, in which six DLR-institutes participate. The aim of the project is to give concrete suggestions for the solution of the problem, how noise in the area of airports can be reduced realistically. Because of the interdisciplinary approach the know-how is brought together by different areas of operation. Measures and its effects can be evaluated and rated more effectively. Technical arrangements are imaginable for example, which would lead to a reduction of noise in the surrounding areas of airports, but cannot be realized out of operational reasons. Therefore at the end of the project new fundamental knowledge is available completed with information about the technical feasibility of the deduced measures and attainments about human’s reactions on traffic noise.