Road traffic noise impacts sleep continuity in suburban residents: Exposure-response quantification of noise-induced awakenings from vehicle pass-bys at night.

Nocturnal traffic noise has been associated with adverse health outcomes in exposed residents. Precise quantification of traffic noise effects on sleep is thus of great importance. Here we establish an exposure-response relationship for the awakening probability due to intermittent road traffic noise in suburban residents. We conducted a field study in residential areas where road traffic was the dominant noise source, and noise events were attributable to separate vehicle pass-bys. Forty healthy participants underwent polysomnography for five consecutive nights at their homes. A total of 11,003 road traffic noises derived from simultaneous acoustic measurements at the sleepers' ears were included in an event-related analysis of awakenings. Logistic regression analysis revealed that the awakening probability due to road traffic noise increased with the maximum sound pressure level (SPL) and the maximum slope of the increasing SPL of a vehicle pass-by, as well as the age of the exposed individual. Compared to sleep stage 2, the awakening probability was higher in rapid eye movement sleep (REMS) and lower in slow wave sleep (SWS). The protective effect of both stage 2 and SWS against awakenings decreased with age, whereas no age-dependent change was observed for REMS. When adjusting for other contributing factors, the probability of a noise-induced awakening ranged from 0% at a maximum SPL of 27.1 dB(A) to 2.0% at 70 dB(A). Road traffic noise at night - even in suburban areas with moderate traffic density - negatively impacts residents' sleep continuity. Exposure-response quantification for traffic noise-induced awakenings may serve as a basis for noise protection efforts by regulators and policy makers.

Short-Term Annoyance Due to Night-Time Road, Railway, and Air Traffic Noise: Role of the Noise Source, the Acoustical Metric, and Non-Acoustical Factors.

Field studies on traffic noise-induced annoyance have predominantly used estimated outside noise levels. We intended to complement existing knowledge with exposure-response relationships that are based on precise indoor noise measurements. Acoustic recordings inside the bedrooms of nightly road traffic and annoyance ratings in the following morning were obtained from 40 suburban residents (mean age 29.1 years ± 11.7; 26 females). We derived exposure-response functions for the probability to be "annoyed at least a little" (%LA). Further analyses compared data from the current study with those from two earlier studies on railway and aircraft noise. Annoyance increased with the number of traffic events and the equivalent sound pressure level. The inclusion of non-acoustical factors (such as assessment of road transport) improved the prediction considerably. When comparing the different traffic noise sources, %LA was higher for road than for air traffic at a given LAeq,night, but higher for road and railway than for air traffic at a given number of noise events. Acoustical as well as non-acoustical factors impact short-term annoyance induced by road, railway, and air traffic. Annoyance varies across noise sources, which may be due to differences in acoustical characteristics or in the temporal noise distribution throughout the night.

Passenger comfort on high-speed trains: effect of tunnel noise on the subjective assessment of pressure variations.

When passing through a tunnel, aerodynamic effects on high-speed trains may impair passenger comfort. These variations in atmospheric pressure are accompanied by transient increases in sound pressure level. To date, it is unclear whether the latter influences the perceived discomfort associated with the variations in atmospheric pressure. In a pressure chamber of the DLR-Institute of Aerospace Medicine, 71 participants (M = 28.3 years ± 8.1 SD) rated randomised pressure changes during two conditions according to a crossover design. The pressure changes were presented together with tunnel noise such that the sound pressure level was transiently elevated by either +6 dB (low noise condition) or +12 dB (high noise condition) above background noise level (65 dB(A)). Data were combined with those of a recent study, in which identical pressure changes were presented without tunnel noise (Schwanitz et al., 2013, 'Pressure Variations on a Train - Where is the Threshold to Railway Passenger Discomfort?' Applied Ergonomics 44 (2): 200-209). Exposure-response relationships for the combined data set comprising all three noise conditions show that pressure discomfort increases with the magnitude and speed of the pressure changes but decreases with increasing tunnel noise. Practitioner Summary: In a pressure chamber, we systematically examined how pressure discomfort, as it may be experienced by railway passengers, is affected by the presence of tunnel noise during pressure changes. It is shown that across three conditions (no noise, low noise (+6 dB), high noise (+12 dB)) pressure discomfort decreases with increasing tunnel noise.