Annoyance: Comparison between One Dominant Source of Noise and Two Source With Equal Noise

Abstract

TM5-O-05 Introduction: Traffic noise from road traffic and railway is an environmental health problem. In Sweden, approximately 25% of the population is exposed to traffic noise above 55 dB outside their houses. Regarding simultaneous exposure to noise from several sources, there is only a limited knowledge. One purpose was to determine whether noise from 2 sources resulted in higher annoyance, compared to noise from one dominant source, under condition that the total noise exposure was the same. Methods: Residents exposed to traffic noise were selected to cover a wide range of sound levels, LAeq24h from 45 dB to over 70 dB. An acoustic consultant assessed sound levels from railway and road traffic separately, using SoundPlan and ArcView. The energy summation model was applied for assessment of the total noise exposure. Noise annoyance was assessed by a questionnaire, with separate questions regarding annoyance from noise from railway, road traffic noise, and the total traffic sound environment. A logistic regression was performed, with annoyance defined as “moderately, very or extremely annoyed.” Results: Analyses showed that the respondents did no add the annoyance from the 2 sources but made an assessment of the total traffic sound situation. For a high total noise exposure (63–72 dB), the annoyance to the total traffic sound environment was higher than annoyance to road traffic, for the same total noise level (McNemar, P < 0.001). A comparison was made between those exposed to noise from one dominant source (Group 1, n = 1270) and those exposed to 2 equally noisy sources (Group 2, n = 683), under condition that the total noise exposure was the same. When the total noise exposure is low, the annoyance is the same for Group 1 and Group 2. But when the total noise exposure is high, the annoyance is higher for those exposed to 2 equally noisy sources (Group 2). The annoyance is significantly higher (P < 0.05) for those displayed to equal noise from railway and road (Group 2), when the total noise exposure is above 58 dB. Discussion and Conclusions: This investigation shows that the annoyance is higher among people simultaneously exposed to high noise from 2 sources (railway and road traffic), compared with when only one dominant source produces the same noise. This shows the importance of assessing the effects of the total noise exposure, not only exposure from separate sources.