Study On Key Technologies Of Environmental Noise Monitoring And Evaluation

Noise pollution threatens people's sanity and quality of life,brings about the dysfunction of human body systems,even adversely affects longevity.In order to actualize the real-time and effective supervision and prevention of noise,the environmental noise monitoring and evaluation technologies are of great concern.However,current technologies of our country are insufficient in the fuzzification of evaluation criteria and unreasonable evaluation parameters,so it is of great importance to study on the key technologies of environmental noise monitoring and evaluation.Based on the analysis of the deficiencies of China's current environmental noise monitoring and evaluation technologies,the in-depth study of the four key technologies which contain the noise monitoring points arrangement,the weighted method of evaluation,the influence factors of noise data and correction of background noise,and the noise prediction has been to put forward combining the characteristics of environmental noise and the trend in development of the technologies.Firstly,the method of noise monitoring points arrangement is studied in this dissertation.In view of the analysis of acoustic propagation property of three noise sources and the typical dispositions of noise sensitive buildings,with the research on national standards and actual engineering requirements,the principles of noise monitoring points arrangement whose key principle is "people-oriented" are perfected.With the guidance of the new principles,the environmental noise monitoring of a enterprise is realized by taking measures with stationing in populous zones,and the results show the correctness and effectiveness of the new principles.The shortcomings of four common objective noise weight methods which only simulate the hearing feelings of human in partial frequencies for a single loudness and can not reflect the different sensitivities of human in different frequencies and different sound pressure levels are reviewed,and the standard equal loudness curves that can give better expression to the subjective feelings of noise are used.Then,the standard equal loudness curves are refined and completed with the conversion between loudness level and sound pressure level and the cubic spline interpolation to achieve a more comprehensive correspondence between the objective linear sound pressure level and the subjective loudness level.Through the look-up table and the conversion,the weighting model based on the equal loudness curves is built,and the weighted soundpressure levels which are calculated by the model can accurately reflect the subjective feelings of noise by simple physical quantity.The errors of monitoring data in the process of transmission,storage and processing are analyzed,and defined that include instrumental error,discretization error,data processing and storage error,and background noise correction error,this result can provide reference for error analysis and control for similar systems.Aiming at the irrationality of single fixed background noise correction method,a 24 hour dynamic background noise curve is constructed.Based on the principle of separation and synthesis of sound,the dynamic background noise correction model is established,with which more detailed and more accordant changes of the measured noise and background noise can be got.On account of the characteristics of noise monitoring data,an environmental noise short-term prediction model based on Support Vector Machine is built,after comparing with other forecasting models,the conclusion that the Support Vector Machine has effectiveness and superiority in the short-term noise prediction can be got,with the model accurate support for noise prevention and control are provided.Finally,the findings of the four key technologies are applied to practical work about environmental noise monitoring and evaluation in a certain area of Sichuan Province,the results indicate the feasibility and effectiveness of the research.These key technologies provide theoretical basis for the more scientific and effective arbitration,law enforcement and prevention of noise,as well as be good for reference to the establishment and further improvement of the similar monitoring and evaluation systems.