Miners are exposed to silica-bearing dust which can lead to silicosis, a potentially fatal lung disease. Currently, airborne silica is measured by collecting filter samples and sending them to a laboratory for analysis. Since this may take weeks, a field method is needed to inform decisions aimed at reducing exposures. This study investigates a field-portable Fourier transform infrared (FTIR) method for end-of-shift (EOS) measurement of silica on filter samples. Since the method entails localized analyses, spatial uniformity of dust deposition can affect accuracy and repeatability. The study, therefore, assesses the influence of radial deposition uniformity on the accuracy of the method. Using laboratory-generated Minusil and coal dusts and three different types of sampling systems, multiple sets of filter samples were prepared. All samples were collected in pairs to create parallel sets for training and validation. Silica was measured by FTIR at nine locations across the face of each filter and the data analyzed using a multiple regression analysis technique that compared various models for predicting silica mass on the filters using different numbers of “analysis shots.” It was shown that deposition uniformity is independent of particle type (kaolin vs. silica), which suggests the role of aerodynamic separation is negligible. Results also reflected the correlation between the location and number of shots versus the predictive accuracy of the models. The coefficient of variation (CV) for the models when predicting mass of validation samples was 4%–51% depending on the number of points analyzed and the type of sampler used, which affected the uniformity of radial deposition on the filters. It was shown that using a single shot at the center of the filter yielded predictivity adequate for a field method, (93% return, CV approximately 15%) for samples collected with 3-piece cassettes. Copyright 2013 American Association for Aerosol Research

中文翻译：

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煤尘在过滤器上的沉积均匀性及其对二氧化硅 FTIR 分析精度的影响

矿工暴露在含二氧化硅的粉尘中，可能导致矽肺病，这是一种可能致命的肺部疾病。目前，空气中的二氧化硅是通过收集过滤器样品并将它们送到实验室进行分析来测量的。由于这可能需要数周时间，因此需要一种现场方法来为旨在减少暴露的决策提供信息。本研究研究了一种现场便携式傅里叶变换红外 (FTIR) 方法，用于对过滤器样品上的二氧化硅进行位移结束 (EOS) 测量。由于该方法需要局部分析，灰尘沉积的空间均匀性会影响准确性和可重复性。因此，该研究评估了径向沉积均匀性对方法准确性的影响。使用实验室产生的 Minusil 和煤尘以及三种不同类型的采样系统，制备了多组过滤器样品。所有样本都成对收集，以创建用于训练和验证的平行集。通过 FTIR 在每个过滤器表面的九个位置测量二氧化硅，并使用多元回归分析技术分析数据，该技术比较了使用不同数量的“分析镜头”预测过滤器上二氧化硅质量的各种模型。结果表明，沉积均匀性与颗粒类型（高岭土与二氧化硅）无关，这表明空气动力学分离的作用可以忽略不计。结果还反映了位置和射击次数与模型预测准确性之间的相关性。根据分析的点数和使用的采样器类型，预测验证样本质量时模型的变异系数 (CV) 为 4%–51%，这影响了过滤器上径向沉积的均匀性。结果表明，对于使用 3 件式磁带收集的样本，在过滤器中心使用单次发射产生的预测性足以满足现场方法的要求（93% 的回报，CV 约为 15%）。版权所有 2013 美国气溶胶研究协会