Hill Ronald H, Ferraro John R, Dodson James L, Hockman Edwin L, McGovern Amy E, Fayerweather William E
a Industrial Hygiene Consultant , Arvada , Colorado.
J Occup Environ Hyg. 2015;12(7):450-7. doi: 10.1080/15459624.2015.1009981.
Asphalt shingle removal (tear-off) from roofs is a major job task for an estimated 174,000 roofers in the United States. However, a literature search showed that there are no published studies that characterize worker inhalation exposures to asphalt particulates during shingle tear-off. To begin to fill this gap, the present study of inhalation exposures of roofers performing asphalt shingle tear-off was undertaken. The airborne agents of interest were total particulate matter (TP) and organic particulates measured as the benzene-soluble fraction (BSF) of total particulate. The study's objectives were to measure the personal breathing zone (PBZ) exposures of roofing tear-off workers to BSF and TP; and to assess whether these PBZ exposures are different from ambient levels. Task-based PBZ samples (typical duration 1-5 hours) were collected during asphalt shingle tear-off from roofs near Houston, Texas and Denver, Colorado. Samples were analyzed for TP and BSF using National Institute of Occupational Safety and Health (NIOSH) Method 5042. As controls, area samples (typical duration 3-6 hours) were collected on the ground near the perimeter of the tear-off project Because of the presence of significant sources of inorganic particulates in the work environment, emphasis was placed on the BSF data. No BSF exposure higher than 0.25 mg/m3 was observed, and 69% of the PBZ samples were below the limit of detection (LOD). Due to unforeseen confounding, however, statistical comparisons of on-the-roof PBZ samples with on-the-ground area samples posed some special challenges. This confounding grew out of the interaction of three factors: statistical censoring from the left; the strong inverse correlation between LOD concentration and sampling duration; and variation in sampling durations between on-the-ground area samples and on-the-roof PBZ samples. A general linear model analysis of variance (GLM-ANOVA) was applied to help address the confounding. The results of this analysis indicate that personal sample BSF results were not statistically significantly different from the background/area samples.
在美国，从屋顶拆除沥青瓦（掀揭作业）是约17.4万名屋顶工的一项主要工作任务。然而，文献检索表明，尚无已发表的研究对工人在掀揭沥青瓦过程中吸入沥青颗粒物的情况进行描述。为了开始填补这一空白，开展了本项针对进行沥青瓦掀揭作业的屋顶工吸入暴露情况的研究。感兴趣的空气传播因子是总颗粒物（TP）和作为总颗粒物苯可溶部分（BSF）测量的有机颗粒物。该研究的目标是测量屋顶掀揭作业工人个人呼吸带（PBZ）中的BSF和TP暴露量；并评估这些PBZ暴露量是否与环境水平不同。在得克萨斯州休斯顿附近和科罗拉多州丹佛附近的屋顶进行沥青瓦掀揭作业期间，采集了基于任务的PBZ样本（典型时长1 - 5小时）。使用美国国家职业安全与健康研究所（NIOSH）方法5042对样本进行TP和BSF分析。作为对照，在掀揭作业项目周边地面采集了区域样本（典型时长3 - 6小时）。由于工作环境中存在大量无机颗粒物来源，重点关注BSF数据。未观察到高于0.25毫克/立方米的BSF暴露，且69%的PBZ样本低于检测限（LOD）。然而，由于意外的混杂因素，将屋顶PBZ样本与地面区域样本进行统计比较带来了一些特殊挑战。这种混杂源于三个因素的相互作用：左侧的统计删失；LOD浓度与采样时长之间的强负相关；以及地面区域样本与屋顶PBZ样本之间采样时长的差异。应用了一般线性模型方差分析（GLM - ANOVA）来帮助解决混杂问题。该分析结果表明，个人样本的BSF结果与背景/区域样本在统计学上无显著差异。
