OP XI – 6 Evaluation and prediction of indoor and outdoor noise differences in residential dwellings using statistical model

Abstract

Background/aimMost epidemiological studies investigating the association between noise exposure and health use modelled outdoor noise estimates as exposure proxy. This study aims to explore the relationship between indoor and outdoor noise at residential dwellings in London and evaluates potential parameters of dwelling ad sound insulation characteristics to predict the indoor exposure.MethodsMeasurements were done at 49 homes mostly in winter and spring seasons when windows are closed. Continuous noise measurement were made inside and outside each home for three consecutive days using an Optimus CR:171B sound level metre. Selected homes were located close to major roads, railway, under an aircraft flight path or any combination of them. Building survey and time activity diaries of the occupants were also collected.ResultsFrom the unadjusted linear regression model, significant associations were found between indoor and outdoor noise for LAeq,16h (β=0.413, 95% Confidence Interval (CI): 0.081–0.745, p=0.016) and Lnight (β=0.332, 95% CI: 0.039 to 0.624, p=0.027). After adjusting for room volume, window size, source of noise, window type and number of occupants, the association remained significant in the adjusted model for LAeq,16h (β=0.378, 95% CI: 0.071 to 0.685, p=0.018) and Lnight (β=0.297, 95% CI: 0.013 to 0.580, p=0.041) with only a small reduced of the β coefficient from the unadjusted model. These linear models yield an explained variance of 64% (adjusted R2) for LAeq,16h and 51% for Lnight. Based on the preliminary analysis, it is predicted that the indoor level could be 60%–70% lower than the outdoor.ConclusionThe wide CI suggests misclassification bias of exposure when conducting epidemiologiocal studies using the outdoor noise estimates. Further analysis will be done to improve the model by adding some more related sound insulation factors.

The Association between environmental noise exposure and primary headache in pediatric population

“…Third, estimating noise exposure based on residential addresses and outdoor measurements, which assumes indoor noise levels, may have introduced bias. Although previous studies have shown a good correlation between indoor and outdoor noise levels [33,34], limitations remain owing to the estimation of noise using Geographic Information System (GIS) spatial analysis for areas without noise information. Because noise measurement points are designated to represent noise levels considering factors such as population and area, our kriging method implemented for areas with a lower priority for measurement may not accurately re ect noise information.…”

Assessment of indoor exposure to outdoor environmental noise and effects on occupant comfort in multi-unit residential buildings

“…The weak correlation between the indoor and outdoor noise observed in this study agrees with the findings of other studies that also found weak associations between indoor and outdoor noise. [29][30][31] These studies, however, were conducted in occupied suites and indoor noise was likely affected by noise generated from occupants' activities. In the current study, measurements were conducted in unoccupied suites and noise from the HVAC systems is identified as the main reason for the weak correlation.…”

“…Graham et al 28 and Pirrera et al 29 measured nighttime noise levels to estimate the indoor exposure levels due to traffic noise. Naim et al 30 measured indoor noise levels due to aircraft, road and railway traffic for 3 days per building. They found a weak correlation between indoor and outdoor noise which they indicate is mainly due to the lack of suitable locations to place the indoor and outdoor noise monitoring stations in occupied buildings.…”