ABSTRACT Aerosol sampling and identification is vital for the assessment and control of particulate matter pollution, airborne pathogens, allergens, and toxins and their effect on air quality, human health, and climate change. In situ analysis of chemical and biological airborne components of aerosols on a conventional filter is challenging due to dilute samples in a large collection region. We present the design and evaluation of a micro-well (µ-well) aerosol collector for the assessment of airborne particulate matter (PM) in the 0.5–3 µm size range. The design minimizes particle collection areas allowing for in situ optical analysis and provides an increased limit of detection for liquid-based assays due to the high concentrations of analytes in the elution/analysis volume. The design of the collector is guided by computational fluid dynamics (CFD) modeling; it combines an aerodynamic concentrator inlet that focuses the aspirated aerosol into a narrow beam and a µ-well collector that limits the particle collection area to the µ-well volume. The optimization of the collector geometry and the operational conditions result in high concentrations of collected PM in the submillimeter region inside the µ-well. Collection efficiency experiments are performed in the aerosol chamber using fluorescent polystyrene microspheres to determine the performance of the collector as a function of particle size and sampling flow rate. The collector has the maximum collection efficiency of about 75% for 1 µm particles for the flow rate of 1 slpm. Particles bigger than 1 µm have lower collection efficiencies because of particle bounce and particle loss in the aerodynamic focusing inlet. Collected samples can be eluted from the device using standard pipettes, with an elution volume of 10–20 µL. The transparent collection substrate and the distinct collection region, independent of particle size, allows for in situ optical analysis of the collected PM. © 2017 American Association for Aerosol Research

中文翻译：

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气动聚焦微孔气溶胶收集器的设计与评价

摘要 气溶胶采样和鉴定对于评估和控制颗粒物污染、空气传播病原体、过敏原和毒素及其对空气质量、人类健康和气候变化的影响至关重要。由于在大型收集区域中稀释样品，因此在传统过滤器上对气溶胶的化学和生物空气传播成分进行原位分析具有挑战性。我们介绍了用于评估 0.5–3 µm 尺寸范围内的空气中颗粒物 (PM) 的微孔 (µ-well) 气溶胶收集器的设计和评估。该设计最大限度地减少了颗粒收集区域，允许进行原位光学分析，并由于洗脱/分析体积中的分析物浓度高而为基于液体的分析提供了更高的检测限。收集器的设计以计算流体动力学 (CFD) 建模为指导；它结合了一个空气动力学集中器入口，将吸入的气溶胶聚焦到一个窄光束中，以及一个将颗粒收集区域限制在微孔体积内的微孔收集器。收集器几何形状和操作条件的优化导致在 µ 井内的亚毫米区域收集到高浓度的 PM。收集效率实验是在气溶胶室中使用荧光聚苯乙烯微球进行的，以确定收集器的性能作为粒度和采样流速的函数。对于 1 slpm 的流速，收集器对 1 µm 颗粒的最大收集效率约为 75%。由于空气动力学聚焦入口中的粒子反弹和粒子损失，大于 1 µm 的粒子具有较低的收集效率。收集的样品可以使用标准移液器从设备中洗脱，洗脱体积为 10–20 µL。透明的收集基板和独特的收集区域，独立于颗粒大小，允许对收集到的 PM 进行原位光学分析。© 2017 美国气溶胶研究协会