METHODS FOR ASSESSING SYNTHETIC TEXTILE DUST EXPOSURE

直到最近，合成纺织品（ST）粉尘被认为很少或没有产生不良呼吸影响。 这部分是因为粉尘的成分被认为是无害的，因为纤维被认为太大而不能存款在暴露工人的下呼吸系统。 由于这些原因，ST粉尘被归类为不受其他管制的颗粒（PNOR）。 最近的研究发现，在低于PNOR允许暴露限值（PEL）的暴露水平下，ST粉尘对急性和慢性呼吸系统的影响。 现在也有证据表明，ST粉尘的一部分可以沉积在肺的所有区域。 为了进行ST粉尘呼吸影响的未来研究，需要改进暴露评估方法，因为标准PNOR方法不能评估ST粉尘成分或可能存款在肺特定区域的ST颗粒尺寸分数。拟议研究的第一部分将调查ST粉尘采样和分析的几种替代方法，并将其与标准PNOR方法进行比较。 在一家大型ST工厂的精加工部门，采用标准和替代空气监测方法，采用并排采样方案，已经收集了54套匹配的空气样本（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。 还将确定沉积在肺的三个区域中的ST粉尘的组成。 将根据空气监测过程中记录的灰尘感觉制定定性ST灰尘暴露措施。 对于每种定量和定性暴露测量，将比较标准和替代方法。 结果将被用来推荐改进的采样和分析方法进行暴露评估ST粉尘在未来的职业流行病学研究调查呼吸道疾病。 拟议研究的第二部分将调查ST粉尘暴露在同一当地纺织厂。 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粉尘控制的ST精加工工艺的特定方面。

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.