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目的比较短时间定点采样和连续长时间个体采样两种测定总粉尘浓度方法的优劣,为电焊烟尘采样方法的选择提供参考。方法对昆山5家企业的25个焊工电焊烟尘作业点分别进行个体采样和定点采样,结果评价依据《工作场所有害因素职业接触限值第1部分:化学有害因素》(GBZ 2.1-2007)进行。结果个体检测结果中由75个TWA值计算的平均值为(4.47±1.88)mg/m3,定点检测中由75个TWA值计算出的平均值为(2.42±1.19)mg/m3,经过双侧t检验比较,差别有统计学意义(t=7.242,P<0.01)。但当浓度较低时,两种方法所测结果差别不大。同时定点检测的TWA值的超标率为14.7%,个体检测的TWA值超标率为53.3%,两者比较,差异亦有统计学意义(χ2=24.99,P<0.01)。结论个体检测比定点检测更能够真实地反映工人接触的危害水平。
OBJECTIVE To compare the advantages and disadvantages of two methods of spot dust concentration determination by short-time fixed-point sampling and continuous long-time individual sampling, and provide references for the selection of welding dust sampling methods. Methods The 25 welding welds of 5 welders in Kunshan were individually sampled and spot-sampled. The evaluation was based on “Occupational exposure limits for workplace hazardous substances - Part 1: Chemical Hazard” (GBZ 2.1-2007). Results The mean value of 75 TWA values in individual test results was (4.47 ± 1.88) mg / m 3, and the average value of 75 TWA values in fixed-point test was (2.42 ± 1.19) mg / m 3. t test, the difference was statistically significant (t = 7.242, P <0.01). However, when the concentration is low, the results of the two methods show little difference. At the same time, the over-standard rate of TWA detected by fixed-point was 14.7%, and the over-standard rate of TWA detected by individual was 53.3%. There was also a significant difference between the two (χ2 = 24.99, P <0.01). Conclusion Individual detection can more accurately reflect the hazard level of workers exposure than the fixed point detection.