Yoshiaki Mishina

Comparison of noise environment of residences in Nagoya, Japan and in Beijing, China

Abstract A social survey based on the noise environment at residential sites both in Nagoya, Japan and in Beijing, China has been carried out. Noise levels have been measured during one day and night at house sites and a social survey of the reactions of residents to the living environment has also been made. The surveys in both cities indicate that the distribution of noise levels is almost the same, but the reactions of residents to the noise environment are quite different. The analysis and results of the surveys and discussion on the difference between the reactions of residents in the two cities to their noise environments are given in this paper.

Reaction to the outdoor noise among inhabitants in Nagoya, Japan and Beijing, China

Inhabitants’ reaction to outdoor noise in Nagoya and in Beijing was surveyed. A questionnaire on noise was conducted with more than 2000 people in Nagoya and more than 1000 in Beijing. They were also asked whether they were sensitive to each of the 37 types of noise sources. The responses of inhabitants to the above questionnaire in Beijing are more sensitive than those in Nagoya to loudness, annoyance, and sleep disturbance. Road traffic noise is the most audible of 37 noise sources in both cities. Sounds of fireworks and sounds from festivals are also highly audible in Beijing. The most annoying noise is one from motorcycle gangs in both cities, and one from construction in Beijing. The annoyance rates in Beijing are higher than those in Nagoya.

The effects of joint distribution of velocity and PWL of vehicles on the road traffic noise

To evaluate the road traffic noise, a simplified traffic model is usually used, that is, a model with vehicles of the same acoustic power and the equal headway distribution. But in an actual road, fast and slow vehicles and noisy and quiet ones are mixed randomly. The resulting increase in Leq due to variance of PWL and velocity of vehicles has been investigated for the following three cases: (1) when variation coefficient δv of velocity of vehicles is rather small (i.e., δv ≪ 1), (2) when the velocity distribution of the vehicles is the normal distribution, or (3) in the case of gamma distribution of the velocities. As the variance of PWL is 2.55–3.27 (according to the results by Y. Watanabe et al.), the estimated increase of Leq is about 1 dB. And as variation coefficient of velocity of vehicles is 0.13–0.18 (according to the published data on Route 1, Route 16, and Meishin highway), the increase of Leq is about 0.1–1.0 dB. Summing up these effects, the increment of Leq is supposed to be 1–2 dB.To evaluate the road traffic noise, a simplified traffic model is usually used, that is, a model with vehicles of the same acoustic power and the equal headway distribution. But in an actual road, fast and slow vehicles and noisy and quiet ones are mixed randomly. The resulting increase in Leq due to variance of PWL and velocity of vehicles has been investigated for the following three cases: (1) when variation coefficient δv of velocity of vehicles is rather small (i.e., δv ≪ 1), (2) when the velocity distribution of the vehicles is the normal distribution, or (3) in the case of gamma distribution of the velocities. As the variance of PWL is 2.55–3.27 (according to the results by Y. Watanabe et al.), the estimated increase of Leq is about 1 dB. And as variation coefficient of velocity of vehicles is 0.13–0.18 (according to the published data on Route 1, Route 16, and Meishin highway), the increase of Leq is about 0.1–1.0 dB. Summing up these effects, the increment of Leq is supposed to be 1–2 dB.