As part of ongoing epidemiological studies for assessing the association between exposure to dust from taconite operations and the development of respiratory diseases, the goal of this study was to reconstruct the exposures of workers to elongate mineral particle (EMP) in the Minnesota taconite mining industry from 1955–2010. Historical NIOSH-7400 and equivalent EMP personal exposure data were extracted from two sources: (1) the Mine Safety and Health Administration (MSHA) online database recorded for all inspection results since 1978 with 655 EMP monitoring records from 1978–2010 for 13 MSHA Mine IDs associated with this study; and (2) the mining companies’ internal monitoring reports contained 96 personal EMP exposure records. NIOSH-7400 EMP personal exposures were measured for workers in different jobs in all active mines in 2010 by obtaining 1,285 personal samples. After data treatment, all data were grouped into seven mines and eight departments. Within each mine-department, the yearly EMP mean concentration in f/cc for each year of operation was predicted using two approaches. The performance of two approaches varied by situation. The assumptions underlying each approach described in this article have limitations. A linear regression based on limited historical measurements and those made in 2010–2011 (Approach 1) does not yield reasonable and plausible values of the slope. Approach 2 assumes that the EMP and the respirable dust in the same department share the same historical time trend. This approach allowed us to avail of the more reasonable slope estimates from the historical respirable dust data set and yielded more plausible historical exposure estimates for most locations. This work with two different job exposure matrix (JEMs) provides a unique research opportunity to study the potential impact of exposure assessment to epidemiological results. Both JEMs are being used to assess associations between EMP and respiratory disease in epidemiological studies.

作为正在进行的流行病学研究的一部分，该评估旨在评估Taconite作业中尘埃暴露与呼吸系统疾病之间的关系，该研究的目的是重建明尼苏达州Taconite采矿业工人暴露于细长矿物质颗粒（EMP）中的暴露。 1955年至2010年。从两个来源中提取了历史性的NIOSH-7400和等效的EMP个人暴露数据：（1）记录了自1978年以来所有检查结果的矿山安全与健康管理局（MSHA）在线数据库，并记录了1978-2010年间13个MSHA矿山的655个EMP监测记录与这项研究相关的ID；（2）矿业公司的内部监控报告包含96个人的EMP暴露记录。在2010年，对所有活跃矿山中从事不同工作的工人的NIOSH-7400 EMP个人暴露进行了测量，得出1，285个个人样本。经过数据处理后，所有数据都分为七个矿山和八个部门。在每个矿山部门中，使用两种方法预测了每个运营年度的年EMP平均浓度（f / cc）。两种方法的性能因情况而异。本文介绍的每种方法所基于的假设都有局限性。基于有限的历史测量值和2010-2011年的测量值进行的线性回归（方法1）无法得出合理且合理的斜率值。方法2假设同一部门的EMP和可吸入粉尘具有相同的历史时间趋势。这种方法使我们能够利用可吸入粉尘历史数据集中的更合理的坡度估算值，并在大多数地方得出更合理的历史暴露估算值。这项使用两个不同的工作暴露矩阵（JEM）的工作为研究暴露评估对流行病学结果的潜在影响提供了独特的研究机会。在流行病学研究中，两种JEM都用于评估EMP和呼吸系统疾病之间的关联。