METHODS FOR ASSESSING SYNTHETIC TEXTILE DUST EXPOSURE

直到最近，合成纺织（ST）粉尘被认为产生很少或没有不利的呼吸影响。这在一定程度上是因为人们认为粉尘的成分是无害的，而且人们认为粉尘中的纤维太大，无法沉积在接触粉尘的工人的下呼吸道系统中。由于这些原因，ST粉尘在分类下进行调节，非其他调节颗粒（PNOR）。最近的研究发现，在远远低于PNOR允许暴露限值（PEL）的暴露水平下，与ST粉尘有关的急性和慢性呼吸效应。现在也有证据表明，一些ST粉尘可以沉积在肺部的所有区域。为了开展ST粉尘呼吸效应的未来研究，需要改进评估暴露的方法，因为标准的PNOR方法不能评估ST粉尘成分或可能沉积在肺特定区域的ST粒度组分。第一部分将研究ST粉尘取样和分析的几种替代方法，并将它们与标准PNOR方法进行比较。在一家大型ST工厂的精加工部门，已经采用标准和替代空气监测方法在并排采样方案中收集了54组匹配的空气样本（258个空气过滤器）。使用这些空气样本，将计算三种不同的定量暴露措施：质量浓度、颗粒数浓度和纤维数浓度。沉积在肺部三个区域的ST粉尘的成分也将被确定。将根据空气监测期间记录的粉尘情况，制定定性的ST粉尘暴露措施。对于每个定量和定性暴露测量，将比较标准和替代方法。研究结果将用于建议改进取样和分析方法，以便在今后调查呼吸道疾病的职业流行病学研究中对ST粉尘进行接触评估。拟议研究的第二部分将调查同一当地纺织厂的ST粉尘暴露情况。将进行统计建模，以确定ST粉尘暴露措施的生产过程决定因素。这些结果将用于帮助工厂针对ST精加工过程的特定方面进行ST粉尘控制。

Until recently, synthetic textile (ST) dust was thought to produce little or no adverse respiratory effects. This is in part because the composition of the dust was considered harmless and because the fibers were thought to be too large to deposit in the lower respiratory systems of exposed workers. For these reasons, ST dust is regulated under the classification, Particulate Not Otherwise Regulated (PNOR). Recent studies have found acute and chronic respiratory effects associated with ST dust at exposure levels well under the PNOR Permissible Exposure Limit (PEL). There is now also evidence that some fraction of ST dust can be deposited in all regions of the lung. To conduct future studies of the respiratory effects of ST dust, improved methods for assessing exposure are needed because the standard PNOR method does not assess the ST dust composition or the ST particle size fractions likely to deposit in specific regions of the lung. Part one of the proposed study will investigate several alternative methods for ST dust sampling and analysis and compare them to the standard PNOR method. Fifty-four matched sets (258 air filters) of air samples have already been collected using standard and alternative air monitoring methods in a side-by-side sampling scheme in a finishing department at a large ST mill. Using these air samples, three different quantitative exposure measures will be calculated: mass concentration, particle number concentration, and fiber number concentration. The composition of the ST dust that deposits in the three regions of the lung will also be determined. Qualitative ST dust exposure measures will be developed based on perceptions of dustiness recorded during the air monitoring. For each quantitative and qualitative exposure measure, the standard and alternative methods will be compared. The results will be used to recommend improved sampling and analytical methods for conducting an exposure assessment for ST dust in future occupational epidemiologic studies investigating respiratory disease. Part two of the proposed study will investigate ST dust exposure in the same local textile mill. Statistical modeling will be preformed to identify the production process determinants of the ST dust exposure measures. These results will be used to assist the mill in targeting specific aspects of the ST finishing process for ST dust control.