Optimization Study On Evaluation Indices Of Non-Gaussian Noise Exposure And Strategic Advice On Reducing Noise Hazards

Background:Industrial noise, especially the non-Gaussian noise has a great impact on human hearing, the harmfulness of noise needs to be examined. There are some evaluation indicators for Gaussian noise but not non-Gaussian noise, also the applicability of those indicators for non-Gaussian noise measurement and evaluation needs further study, and some research needs to be done in order to find out a better measurement for the exposure of complex noise.Objective:(1) Build up a database for the result of industrial noise examination in Zhejiang province and a database for the exposure of industrial noise and the hearing lose condition of workers,to find out the risk prevalence of industrial noise and the relationship between complex noise exposure and hearing loss.(2) Establish a method system for the complex noise evaluation index comparison to make sure the application and advantage of those indicators for complex noise measurement and evaluation,and a new energy index optimization method is derived to explore a index which has a better applicability for complex noise exposure assessment.(3) Give some strategic advises according to the aspects such as the criteria of noise measurement and evaluation, the laws of noise noise monitoring,hearing protection and the enterprise management.Methods:The enterprises in Zhejiang province was accordanced with the scale, industry, region grouping, the noise qualification rate of each group was compared; 898 workers in 17 enterprises exposed to noise as the research object. Personal LAeq.8h and LEX.8h was determined by a noise dose meter. CNE was calculated through combing LAeq.8h and its corresponding exposure periods. A new index was calculated through adjusting the CNE by noise fluctuation. Meanwhile, questionnaire and hearing loss test were performed for all subjects.Using the correlation analysis, correlation test and multiple factor analysis, logistic regression analysis to compare the relationship between different indices and hearing loss.Results:(1) The industrial noise passing rate of enterprises in Zhejiang Province was 69.71%, and the passing rate of enterprises differed in sizes, types of industry and areas.(2) The average noise intensity level of seventeen factories was 92.73±7.24dB. 32.07% of workers had high frequency hearing loss, and the frequency loss rate of workers was 20.38%.(3) The hearing lose degree was effected by noise intensity, period of noise exposure and noise fluctuation.(4) The k-value used to adjust the CNE is 0.77,the correlation coefficient between CNE’and hearing loss was higher than that between CNE and hearing loss. The partial regression sum of squares of CNE1 is higher than CNE.Conclusions:(1) The passing rate of industrial noise in Zhejiang province is still at a relatively low level, the midsize enterprises and industries of mining,construction and manufacturing should be the focus of noise regulation management.(2) The hearing loss situation of workers is seriously.there is a relationship between hearing loss and exposure conditions such as noise intensity,noise exposure period and noise fluctuation.Higher noise intensity, longer noise exposure and bigger noise fluctuation will make hearing loss worse.(3) The adjusted cumulative noise exposure index makes a consideration of noise intensity, period of noise exposure and noise fluctuation, the rank of hearing loss index for hearing loss evaluation are as follows:CNE’> CNE.