Social Investigation On Urban Traffic Noise Subjective Annoyance

Several traffic noise polluted residential areas (with one or several of the following noises as road traffic noise, rail traffic noise, railway noise and airport noise) were selected to investigate the influence of combined traffic noise pollution on urban residents in the cities of Dalian, Shanghai, Hangzhou and Yuyao. According to the traffic flow and the distribution of buildings and landform, the software Cadna/A was used to estimate the day-night equivalent noise level (Ldn) one meter outside windows of each building. The estimated data was modified according to the actual metrical data. The interpolation was used to estimate the weighted effective continuous perceived noise levels (LWECPN) in different areas around the airport, and the graph of equal noise level contours was drawn. Several community surveys on noise subjective annoyance were carried out face to face among 5700 local residents aged 15 to 75 years old, using the ICBEN scale.4995 valid questionnaires were gotten. According to the results, we obtained the relationship curves between percentage of "highly annoyed" persons (%HA) and Ldn contributed by single traffic noise, dominant traffic noises and the road-railway (rail traffic-road) combined traffic noise, respectively. The membership function was used to calculate annoyance threshold of exposure to different traffic noises.In the survey on the road-railway combined traffic noise, the results showed that to the northerners, at high sound level (Ldn> 64.0dB), there was small difference between %HA due to road traffic noise and railway noise with the same Ldn; at low sound level (Ldn< 64.0 dB), the intermittent railway noise would induce more annoyance. But the southerners felt more annoyance induced by the road traffic noise with the same Ldn. According to dominant noise sources and road-rail combined traffic noise, it was shown that in areas exposed to road-rail combined traffic noise, %HA by the total traffic noise was significantly higher than in areas with one dominant noise source (rail or road traffic) with the same Ldn.This interaction effect was significant from 63.5dB and increased gradually with higher sound levels to northerners. The southerners felt that the road-rail combined traffic noise was the most annoying.In the survey on the rail traffic-road combined traffic noise, the results showed that according to dominant traffic noises and the rail traffic-road combined traffic noise, when Ldn> 61.5 dB,%HA induced by the latter was between that of road dominant traffic noise and rail traffic dominant noise with the same Ldn.The results showed that road traffic noise could mask the low frequency dominant and vibrational rail traffic noise at higher sound level (> 61.5 dB). When Ldn< 59.0 dB, for the influence of the visibility of the noise source and vibration damping,%HA induced by the rail traffic dominant noise was the lowest.According to the survey on the noise annoyance in Hangzhou Xiaoshan International Airport, the results showed that if LWECPN was 64.3 dB (Ldn was 51.4 dB), then 15% respondents were highly annoyed. If LWECON was 68.1 dB (Ldn was 55.0 dB), then 25% respondents were highly annoyed. The annoyance threshold of aircraft noise (LWECPN) was 73.7 dB, while the annoyance threshold of a single flight incident instantaneous noise level was 72.9 dB.