Effects of nocturnal air and rail traffic noise on sleep

Undisturbed and sufficiently long sleep is a prerequisite for a healthy life as well as for the prevention of fatigue-induced accidents. Especially the increasing air and freight rail traffic is more and more shifted to shoulder and night-time hours due to missing capacity and infrastructure during daytime. Thus, the sleep of residents near airports or railway tracks is increasingly affected by traffic noise. Only very few main airports, such as Frankfurt (Germany), implemented a night flight ban in order to countervail this trend. Since 1999 the Institute of Aerospace Medicine of the German Aerospace Center (DLR) has investigated these night time noise effects in several field studies in which the sound pressure levels LAS and LAF and sound files were continuously measured with class one sound level meters at the sleeper’s ear. Sleep structure was recorded with polysomnography (simultaneous measurement of brain waves, eye movements, and muscle tone), the gold-standard to quantify sleep objectively. The results on sleep quality and additional awakening reactions due to traffic noise from former studies performed at Cologne/Bonn airport (high night time traffic) and a busy railway track in the Rhine valley (high night time freight traffic) are compared with the results of the recently completed NORAH (Noise-Related Annoyance, Cognition, and Health) study at Frankfurt airport. In the latter study data were collected both before as well as after the implementation of a ban of night flights between 11 p.m. and 5 a.m.. Sound exposure distributions, average sound levels and sound level rise time distributions at the sleepers’ ear are presented for all three studies.