Koehler Kirsten A, Anthony T Renee, Van Dyke Michael, Volckens John
Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1681, USA.
Ann Occup Hyg. 2012 Mar;56(2):194-206. doi: 10.1093/annhyg/mer077. Epub 2011 Sep 29.
The objective of this study was to examine the facing-the-wind sampling efficiency of three personal aerosol samplers as a function of particle phase (solid versus liquid). Samplers examined were the IOM, Button, and a prototype personal high-flow inhalable sampler head (PHISH). The prototype PHISH was designed to interface with the 37-mm closed-face cassette and provide an inhalable sample at 10 l min(-1) of flow. Increased flow rate increases the amount of mass collected during a typical work shift and helps to ensure that limits of detection are met, particularly for well-controlled but highly toxic species. Two PHISH prototypes were tested: one with a screened inlet and one with a single-pore open-face inlet. Personal aerosol samplers were tested on a bluff-body disc that was rotated along the facing-the-wind axis to reduce spatiotemporal variability associated with sampling supermicron aerosol in low-velocity wind tunnels. When compared to published data for facing-wind aspiration efficiency for a mouth-breathing mannequin, the IOM oversampled relative to mannequin facing-the-wind aspiration efficiency for all sizes and particle types (solid and liquid). The sampling efficiency of the Button sampler was closer to the mannequin facing-the-wind aspiration efficiency than the IOM for solid particles, but the screened inlet removed most liquid particles, resulting in a large underestimation compared to the mannequin facing-the-wind aspiration efficiency. The open-face PHISH results showed overestimation for solid particles and underestimation for liquid particles when compared to the mannequin facing-the-wind aspiration efficiency. Substantial (and statistically significant) differences in sampling efficiency were observed between liquid and solid particles, particularly for the Button and screened-PHISH, with a majority of aerosol mass depositing on the screened inlets of these samplers. Our results suggest that large droplets have low penetration efficiencies through screened inlets and that particle bounce, for solid particles, is an important determinant of aspiration and sampling efficiencies for samplers with screened inlets.
本研究的目的是考察三种个人气溶胶采样器的迎风采样效率与颗粒相（固体与液体）之间的关系。所考察的采样器有IOM、纽扣式采样器以及一种原型个人高流量可吸入采样头（PHISH）。原型PHISH设计用于与37毫米封闭式采样盒连接，并以10升/分钟的流量提供可吸入样本。提高流速可增加在典型工作班次期间收集的质量，并有助于确保达到检测限，特别是对于控制良好但毒性很强的物质。测试了两种PHISH原型：一种带有筛网入口，另一种带有单孔开放式入口。个人气溶胶采样器在一个钝体圆盘上进行测试，该圆盘沿迎风轴旋转，以减少与在低速风洞中采样超微米气溶胶相关的时空变异性。与已发表的口呼吸人体模型迎风抽吸效率数据相比，对于所有尺寸和颗粒类型（固体和液体），IOM相对于人体模型迎风抽吸效率存在过采样。对于固体颗粒，纽扣式采样器的采样效率比IOM更接近人体模型迎风抽吸效率，但筛网入口去除了大部分液体颗粒，导致与人体模型迎风抽吸效率相比有很大低估。与人体模型迎风抽吸效率相比，开放式PHISH的结果显示对固体颗粒存在高估，对液体颗粒存在低估。在液体和固体颗粒之间观察到采样效率存在显著（且具有统计学意义）差异，特别是对于纽扣式采样器和带筛网的PHISH，大部分气溶胶质量沉积在这些采样器的筛网入口上。我们的结果表明，大液滴通过筛网入口的穿透效率较低，并且对于固体颗粒而言，颗粒反弹是带筛网入口采样器抽吸和采样效率的重要决定因素。
