De Vocht Frank, Hirst Adrian, Gardner Anthony
Occupational and Environmental Health Research Group, School of Translational Medicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester M13 9PL, UK.
Ann Occup Hyg. 2009 Jan;53(1):19-25. doi: 10.1093/annhyg/men068. Epub 2008 Oct 31.
Institute of Occupational Medicine dual-fraction samplers equipped with porous polyurethane foam inserts have been introduced as a cheaper alternative to cyclone pre-selectors for measuring respirable dust. Initial data from a variety of industries suggested that the dual-fraction sampler yielded similar results as personal cyclones and that the respirable selection of the foam was not adversely affected by particle loading. We conducted a similar study, but specifically in the brick industry to assess the validity of this dual-fraction sampler as an alternative to personal cyclones in this industry. A total of 72 side-by-side samples using Higgins-Dewell cyclones and dual-fraction samplers were taken in seven UK factories manufacturing a variety of bricks. A priori measurements were assigned to any of the three groups based on the dominant source of the particulates in the exposure matrix (clay, sand or mixed) at the location in the factories where the measurements were taken. After log transformation, Higgins-Dewell cyclone-measured concentrations were on average 1.9 times higher than the concentrations measured by the dual-fraction samplers, with a Pearson correlation of 0.78 (95% confidence interval 0.66-0.85). Stratified analysis by main source of exposure suggested that the correlation was best for silica dust-based exposures r(p) = 0.88 (0.63-0.96), but decreased with the relative importance of clay particulates in the exposure matrix to r(p) = 0.82 (0.59-0.93) in the 'mixed-source' group and r(p) = 0.74 (0.55-0.85) in the 'clay particulates' group. Similarly, performance of the dual-fraction sampler relative to the cyclone sampler was negatively associated with increased relative importance of clay particulates in the exposure matrix and ranged from similar measured concentration beta = 0.96 (0.54-1.39) for silica to 50% under sampling beta = 0.50 (0.33-0.67) for clay particulates. These results suggested that the overall performance of the dual-fraction sampler in the brick industry depends on the relative importance of clay particulates in the exposure matrix. As such, results from occupational hygiene compliance surveys close to the occupational exposure limit can lead to erroneous decisions on compliance.
职业医学研究所配备多孔聚氨酯泡沫滤芯的双级分采样器，已作为一种比旋风预分选器更便宜的可吸入粉尘测量替代设备被引入。来自多个行业的初步数据表明，双级分采样器产生的结果与个人旋风采样器相似，并且泡沫的可吸入性选择不受颗粒负载的不利影响。我们进行了一项类似的研究，但专门针对制砖行业，以评估这种双级分采样器作为该行业个人旋风采样器替代品的有效性。在英国七家生产各种砖块的工厂中，共使用希金斯 - 杜威尔旋风采样器和双级分采样器并排采集了72个样本。根据测量地点暴露基质中颗粒物的主要来源（粘土、沙子或混合），将先验测量值分配到三个组中的任何一组。经过对数转换后，希金斯 - 杜威尔旋风采样器测量的浓度平均比双级分采样器测量的浓度高1.9倍，皮尔逊相关系数为0.78（95%置信区间0.66 - 0.85）。按主要暴露源进行的分层分析表明，对于基于二氧化硅粉尘的暴露，相关性最佳，r(p)=0.88(0.63 - 0.96)，但随着粘土颗粒在暴露基质中的相对重要性增加，相关性降低，在“混合源”组中降至r(p)=0.82(0.59 - 0.93)，在“粘土颗粒”组中降至r(p)=0.74(0.55 - 0.85)。同样，双级分采样器相对于旋风采样器的性能与粘土颗粒在暴露基质中的相对重要性增加呈负相关，范围从二氧化硅的类似测量浓度β = 0.96(0.54 - 1.39)到粘土颗粒的采样不足50%，β = 0.50(0.33 - 0.67)。这些结果表明，双级分采样器在制砖行业的整体性能取决于粘土颗粒在暴露基质中的相对重要性。因此，职业卫生合规调查接近职业接触限值的结果可能会导致关于合规性的错误决策。
