Bracken T D, Rankin R F, Senior R S, Alldredge J R, Sussman S S
T. Dan Bracken, Inc., Portland, Oregon 97202, USA.
Bioelectromagnetics. 1995;16(4):216-26. doi: 10.1002/bem.2250160403.
The Electric and Magnetic Field Measurement Project for Utilities--the Electric Power Research Institute (EPRI) Electric and Magnetic Field Digital Exposure (EMDEX) Project (the EPRI EMDEX Project)--was a multifaceted project that entailed technology transfer, measurement protocol design, data management, and exposure assessment analyses. This paper addresses one specific objective of the project: the collection, analysis, and documentation of power-frequency magnetic field exposures for a diverse population of utility workers. Field exposure data measured by an EMDEX system were collected by volunteer utility employees at 59 sites in four countries between September, 1988, and September, 1989. Specially designed sampling procedures and data collection protocols were used to ensure uniform implementation across sites. Volunteers within 13 job classifications recorded which of eight work or three nonwork environments they occupied while wearing an EMDEX meter. Approximately 50,000 hours of magnetic field exposure records taken at 10 s intervals were obtained, about 70% of which were from work environments. Exposures and time spent in environments were analyzed by primary work environment, by occupied environment, and by job classification. Generally, for utility-specific job classifications related to the generation, transmission, and distribution of electricity, the field and exposure measurements in terms of workday mean field were higher than in more general occupations. The job classifications with the highest (median workday mean) exposure were substation operators (0.7 microT) and electricians (0.5 microT). Total variance also tended to be largest for utility-specific job classifications. For these workers, the contributions of between-worker and within-worker variances to total variance were about the same. Measurements in utility-specific environments were higher than in more general environments. Estimates of time-integrated exposure indicated that utility-specific job classifications received about one-half or more of their total exposure on the job. The nonwork field and exposure distributions for workers in all job categories were comparable with median nonworkday means of about 0.09 microT.
公用事业公司的电场和磁场测量项目——电力研究所在线电场和磁场数字暴露（EMDEX）项目（电力研究所EMDEX项目）——是一个多方面的项目，涉及技术转让、测量协议设计、数据管理和暴露评估分析。本文阐述了该项目的一个具体目标：收集、分析和记录不同类型公用事业工人的工频磁场暴露情况。1988年9月至1989年9月期间，由志愿者公用事业员工在四个国家的59个地点收集了通过EMDEX系统测量的现场暴露数据。采用了专门设计的采样程序和数据收集协议，以确保各地点的统一实施。13个工作分类中的志愿者在佩戴EMDEX测量仪时记录了他们所处的8种工作环境或3种非工作环境中的哪一种。获得了大约50000小时以10秒为间隔的磁场暴露记录，其中约70%来自工作环境。按主要工作环境、所处环境和工作分类对暴露情况和在各环境中花费的时间进行了分析。一般来说，对于与发电、输电和配电相关的特定公用事业工作分类，工作日平均场强的现场和暴露测量值高于更一般的职业。暴露量最高（工作日平均中位数）的工作分类是变电站操作员（0.7微特斯拉）和电工（0.5微特斯拉）。特定公用事业工作分类的总方差也往往最大。对于这些工人，工人间方差和工人内方差对总方差的贡献大致相同。特定公用事业环境中的测量值高于更一般的环境。时间积分暴露估计表明，特定公用事业工作分类的工人在工作中接受的总暴露约占一半或更多。所有工作类别的工人的非工作场强和暴露分布与非工作日平均中位数约为0.09微特斯拉相当。
