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Nocturnal road traffic noise assessment and sleep research: The usefulness of different timeframes and in- and outdoor noise measurements
Applied Acoustics, (2011)
Аннотация
In this paper, we investigated the procedure of noise assessment in
the study of nocturnal noise exposure during sleep in the home situation.
The use of two different timeframes (fixed from 11 PM to 07 AM versus
personal “Time in Bed” period) was explored as well as the relation
between indoor and outdoor noise levels and between the actual and
estimated noise levels. Noise recordings were performed inside and
outside the bedroom of 24 subjects living in high density road traffic
noise areas in the Brussels’ Capital Region during seven consecutive
days. Indoor and outdoor noise indicators LAeq, LAmax and individual
noise events were analysed. Subjects completed a daily sleep log
in which the Time in Bed period was assessed. The results indicate
that, for outdoor noise assessment, the use of an average LAeq might
not be sufficient to reflect well the noise levels during the sleep
period. For indoor measurements, significant differences were found
in the comparison between both timeframes (LAeq: T = 16; p < .001).
Considering the relation between indoor and outdoor measurements,
low correlations (r = .49; p < .001) were found even when the location
of the bedroom as a mediating factor was accounted for (street side;
r = .52; p < .001). Therefore, from our study, caution is needed
when relying on outdoor noise measurements for the evaluation of
sleep disturbances. Furthermore, one needs to be aware of the weak
correspondence between indoor and outdoor noise levels in the discussion
of what a harmonized noise indicator for the evaluation of noise
exposure and sleep disturbances should consist of.
