Cheng Xiaoru

Objective Comparing dose-response relationship for continuous noise induced hearing loss with sound pressure level,L Aeq.8h and cumulative noise exposure.Methods Four groups of textile workers were designed as investigating subjects,three to five workers were selected to measure L Aeq.8h with dosimeter for each group in each shift workday.L Aeq.1 min were measured with sound level meter and lattice sampling method in same workshops.Questionnaire and hearing measurement were carried out in the 163 textile workers.Results The adjusted prevalence of high frequency noise induced hearing loss(HFNIHL)was 64.4%(105/163),and the adjusted prevalence of low frequency noise induced hearing loss was 2.5%(4/163).The prevalence of HFNIHL was increased in higher noise exposure groups,that means there was a typical dose-response relationship for noise induced HFNIHL in the continuous noise exposure population.Trend chi-square and logistic model analysis showed that cumulative noise exposure(CNE)and L Aeq.8h assessment model was better than other models by dose-response assessment.Conclusion CNE and L Aeq.8h assessment model is one of the best potential candidate models for assessing industrial continuous noise exposure,it needs more observation in different kinds of industrial noise exposure population to confirm the hypothesis.

[Objective]To observe and compare personal noise exposure level variations between workers and workdays. [Methods]Four textile workers and four mechanical manufacture workers were selected to measure personal noise exposure level in eight hours(LAeq.8h)with dosimeter for three workdays.[Results]The result showed that the textile workers exposed to continuous noise,and the mechanical manufacture workers exposed to non-continuous noise. The maximum,minimum and range of twelve LAeq.8h measurements in textile workers were 99.2,92.8 and 6.4 dB(A),and those in mechanical manufacture workers were 89.9,83.1 and 6.8 dB(A). The maximum and minimum for mean of LAeq.8h in each shift workday in textile workers were(98.0± 1.1)and(94.3±1.5)dB(A),and those in each workday in mechanical manufacture workers were(87.9±1.0)and(85.1±1.5) dB(A). The maximum and minimum for mean of LAeq.8h in each textile worker were(96.2±2.2)and(95.8±2.0)dB(A),and those in mechanical manufacture worker were(87.1±3.0)and(86.1±2.1)dB(A). The results showed that the level of personal noise exposure for one worker in one day or more than one day could not accurately represent one group workers’noise exposure,but the results from four workers in one day could.[Conclusion]It suggested that the results of personal noise exposure for a few workers within one day could be used to assess the noise exposure level of one group workers.