目的:评估水泥生产工人的个人胸腔粉尘样品中的组成和对熟料和其他特定成分的暴露。
方法:基于分类树开发了一种用于对水泥生产工厂中的空气传播颗粒进行分类的程序。为此,29个材料样品中27,217个颗粒的化学成分(熟料,石灰石,石膏,粘土,石英,铝土矿,铁源,粉煤灰,和煤)通过扫描电子显微镜(SEM)和能量色散X射线显微分析(EDX)自动确定。水泥中主要元素的浓度(钙,铝,硅,铁,和硫)用于分类。在材料样品中获得的分类树的分割标准用于对34个个人胸部气溶胶样品中的44,176个颗粒进行分类。对熟料和其他材料的含量进行了估算,并对熟料含量进行了统计分析,以了解工作类型和工作任务之间的差异。
结果:材料样品中64%至88%的颗粒被归类为实际材料。具有可变成分的材料类型(粘土,粉煤灰,和煤炭)被归类为最低一致性(64%至67%),而成分变化更有限的材料(熟料,石膏,和石英)分类更一致(76%至85%)。个人样品中熟料含量的算术平均值(AM)为62.1%,中位数为55.3%,95%置信区间(CI)为42.6%至68.1%。在工作类型之间没有观察到显著差异。然而,当工人处理高熟料含量的材料时,样品中的熟料含量明显高于处理低熟料含量的材料时,85%对65%(P=0.02)。石灰石含量为14.8%,中位数13.2%(95%CI5.5至20.9),而其他材料的相对丰度中位数≤6.4%。
结论:通过SEM-EDX进行自动颗粒分析,然后进行分类树分析,量化的熟料与预期在水泥生产工厂中空气传播的原材料一起评估时具有相当高的一致性。工作类型的熟料比例相似。按假定的熟料含量进行先验排序的任务有明显不同,并且根据预期,这支持所选方法的有效性。
结论:水泥生产行业中矿物气溶胶的个人样品的组成可以通过使用SEM-EDX进行自动单颗粒分析并通过分类树程序进行分类来估算。熟料是水泥生产工人接触的胸腔气溶胶的主要成分。工作类型之间的差异相对较小且不显著。来自任务的熟料含量与假设一致。
To estimate the composition and exposure to clinker and other specific components in personal thoracic dust samples of cement production workers.
A procedure for the classification of airborne particles in cement production plants was developed based on classification trees. For this purpose, the chemical compositions of 27,217 particles in 29 material samples (clinker, limestone, gypsum, clay, quartz, bauxite, iron source, coal fly ash, and coal) were determined automatically by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). The concentrations of the major elements in cement (calcium, aluminium, silicon, iron, and sulphur) were used for the classifications. The split criteria of the classification trees obtained in the material samples were used to classify 44,176 particles in 34 personal thoracic aerosol samples. The contents of clinker and other materials were estimated, and the clinker contents were analysed statistically for differences between job types and job tasks.
Between 64% and 88% of the particles from material samples were classified as actual materials. The material types with variable composition (clay, coal fly ash, and coal) were classified with the lowest consistency (64% to 67%), while materials with a more limited compositional variation (clinker, gypsum, and quartz) were classified more consistently (76% to 85%). The arithmetic mean (AM) of the clinker content in personal samples was 62.1%, the median was 55.3%, and 95% confidence interval (CI) was 42.6% to 68.1%. No significant differences were observed between job types. However, the clinker content in samples when workers handled materials with high clinker content was significantly higher than when materials with lower clinker content were handled, 85% versus 65% (P = 0.02). The limestone content was AM 14.8%, median 13.2% (95% CI 5.5 to 20.9), whereas the other materials were present with relative abundances of median ≤ 6.4%.
Automated particle analysis by SEM-EDX followed by classification tree analysis quantified clinker with fairly high consistency when evaluated together with raw materials that are expected to be airborne in cement production plants. The clinker proportions for job types were similar. Tasks a priori ranked by assumed clinker content were significantly different and according to expectations, which supports the validity of the chosen methodology.
The composition of personal samples of mineral aerosols in the cement production industry could be estimated by automated single particle analysis with SEM-EDX and classification by a classification tree procedure. Clinker was the major component in the thoracic aerosol that cement production workers were exposed to. Differences between job types were relatively small and not significant. The clinker content from tasks was in agreement with assumptions.