Wenzl T B, Kriebel D, Eisen E A, Tolbert P, Hallock M
Department of Work Environment, University of Massachusetts, Lowell, USA.
Arch Environ Health. 1997 May-Jun;52(3):227-32. doi: 10.1080/00039899709602891.
Inconsistent findings from recent mortality studies of workers exposed to magnetic fields have led to calls for more detailed understanding of exposure distributions and metrics in various industries. The authors undertook personal monitoring at an automobile transmission plant to (a) learn if magnetic field exposure differences were present, (b) make assignments for a brain cancer study, and (c) compare two exposure indices. A wide range of average exposures occurred (i.e., 0.016-4.6 microtesla). Within-day variability was also large, and it reached 4 orders of magnitude for some workers. Unexpectedly, demagnetizers were found among the strong sources that contributed to elevated exposures. The authors used conventional summary measures to assign job groups to exposure categories, and they used a new index of exposure irregularity to make alternative assignments. These new assignments appeared to differ from the original ones with respect to work time in each exposure group (i.e., 54% of the work time fell into different exposure categories).
近期针对暴露于磁场中的工人进行的死亡率研究结果并不一致，这引发了人们对于更详细了解各行业暴露分布和指标的呼吁。作者在一家汽车变速器工厂进行了个人监测，目的是：(a) 了解是否存在磁场暴露差异；(b) 为一项脑癌研究进行分组；(c) 比较两种暴露指数。监测发现平均暴露范围很广（即0.016 - 4.6微特斯拉）。日内变化也很大，部分工人的变化达到了4个数量级。出人意料的是，在导致暴露水平升高的强源中发现了去磁器。作者使用传统的汇总测量方法将工作小组分配到暴露类别中，并使用一种新的暴露不规则指数进行了替代分组。这些新分组在每个暴露组的工作时间方面似乎与原来的分组不同（即54%的工作时间属于不同的暴露类别）。
