Residential Area, The Characteristics Of Ambient Noise And Annoyance

As the developping of urban modernization, community noise much more sericeous than before. It's shown that noises of public equipments have become the most distinct noise source instead of acticity noise, and in which low frequency noise contributes a lot. While our noise evaluation system is depend on A-weight sound level, which is based on human's response to loudness, so it is necessary to carry out a study to find out whether A-weighted sound level is fit for the evaluation of low frequency noise. On account of the above reasones, noises of public equipments are sampled and analized, and then the relation between noises and noise annoyance is studied through laboratory study and field study. So the study on acoustic characteristic of public equipments in residential area and evaluation criterions in accord with Chinese situation is of practical and referencial means.In this paper, we divided stationary equipments around residential areaes into four types, which are power supply system, water pipe net, air conditioning system and underground garage. Then typical noises of these sources are sampled and analized. Results show that the low frequency noise is dominant in community noise.Laboratory study is adopted to observe the relation between noise stimulus and annoyance. Results indicate that while subjects were exposed to a shot period of time, a closely correlation exhibit between A-weighted sound level and noise annoyance, evaluation of L₅₀ is more appropriate, PNC curve is superior to NR curve, and binomial fit is the best of all fit means. And it shows that application of AHP (Analytic hierarchy process) method into field study is more reasonable and universal.One of the innovations in this paper is that through the calculation of noise energy in low frequency, intermediate frequency and high frequency, dominant frequency is finded by principal component analysis. Another innovation is that latine square design is introduced into the design of laboratory study, which avoids the appearance of order effect.