Author(s): Smith Michael, Ögren Mikael, Ageborg Morsing Julia, Jerson Tomas, Persson Waye Kerstin
In residential areas around railway tunnels, there is no direct airborne noise from the railways, but residents may be exposed to ground borne noise. Nocturnal airborne railway noise has been shown to be potentially disruptive to sleep, but there is only limited previous research on the effects of ground borne railway noise. Here we present laboratory studies investigating how ground borne railway noise at levels occurring in the field impacts on sleep. \nData on sound pressure level, duration and frequency content of ground borne noise from railways were collected from the scientific literature, from measurement reports and by renewed measurements at a few locations in Stockholm, Sweden. Using these data as input, the exposures for the sleep studies were synthesised to represent the variation seen in the gathered data. An initial pilot study (n=5) investigated possible differential effects of frequency content and duration (passenger vs. freight trains). Data from the pilot study implicated very low frequency train passages as potentially disruptive for sleep. The following primary study (n=23) therefore further examined frequency content, and additionally examined the effect of noise level. Across both studies, young and healthy individuals spent five nights in a laboratory furnished to resemble an apartment. The first night was for adaptation to the study setting. The following four nights included a single quiet night to obtain baseline sleep, and three exposure nights involving synthesised ground borne noise from passenger and freight trains. Effects on sleep physiology and self-reported sleep outcomes were obtained using polysomnography and questionnaires respectively. The study findings will be presented at the conference.
Name: Dr Michael Smith