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[目的 ]探讨生产场所矽尘环境瞬时浓度 (EIC)与其时间加权平均浓度 (TWA)间的关系。 [方法 ]在铸造厂、耐火材料厂和锡矿同时测定矽尘EIC和TWA。提出理想瞬时浓度的概念 ,基于理想瞬时浓度及其取值集合S的共同框架来分析EIC与TWA两者的关系 ,推导出TWA理论 =μeσ2 / 2 。以该公式将上述 3家厂矿EIC换算为理论TWA ,并与相应TWA实测值比较。 [结果 ]理论与实测TWA间的差别在耐火材料厂和锡矿均无显著性 (t =1.961和t =1.746,均P >0 0 5 ) ,该公式成立 ,而在铸造厂则否 (t=7.772 ,P <0 .0 5 )。 [结论 ]生产性矽尘EIC与TWA之间在多数情况下存在一定的函数关系 ,经TWA理论 =μeσ2 / 2可将EIC转换为TWA ,这对于我国制订粉尘职业接触限值时确定其TWA限值 ,以及对于TWA的上限值容许上移多少这一国际上有争论的问题均有指导作用
[Objective] The research aimed to discuss the relationship between the instantaneous concentration (EIC) of silica in the production site and its time-weighted average concentration (TWA). [Method] Simultaneous determination of silica dust EIC and TWA in foundry, refractory plant and tin mine. The concept of ideal instantaneous concentration is proposed. The relationship between EIC and TWA is analyzed based on the common framework of ideal instantaneous concentration and its set S, and the TWA theory is deduced as μeσ2 / 2. Using the formula, the above three factories and mines are converted into theoretical TWA EIC, and compared with the corresponding TWA measured value. [Result] The difference between theoretical and measured TWA was not significant in refractories plants and tin mines (t = 1.961 and t = 1.746, all P> 0.05) = 7.772, P <0.05). [Conclusion] There was a certain functional relation between productive silica dust EIC and TWA in most cases. By TWA theory = μeσ2 / 2, EIC could be converted into TWA, which could be used to determine the TWA limit when formulating dust occupational exposure limit Value, and the question of how much the TWA cap is allowed to move up is internationally instructive