Comparative efficiency of airborne pollen concentration evaluation in two pollen sampler designs related to impaction and changes in internal wind speed
Comparative efficiency of airborne pollen concentration evaluation in two pollen sampler designs related to impaction and changes in internal wind speed
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DOI：
10.1016/j.atmosenv.2019.01.039
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发表时间：
2019-04-15
影响因子：
5
通讯作者：
Nakamura, Kimihito
中科院分区：
文献类型：
--
作者：
Miki, Kenji;Kawashima, Shigeto;Nakamura, Kimihito
世界各地使用各种采样方法进行花粉采样。然而，这些方法的采样效率仍不清楚。本文通过对Sigma-2双层气溶胶采样器和赫斯特型风向标式气溶胶采样器采样效率的比较，揭示了采样器物理特性与采样效率之间的关系。初步结果表明，前者具有较高的采样效率。为了进一步探索这一发现，我们开发了一个基于1）花粉粒浓度连续性方程和2）撞击理论的理论。应用我们开发的理论的实验结果表明，冲击是一个显着的贡献者相对较高的采样效率的两层采样入口，由于较大的横截面积的两层入口和采样器内采样花粉粒的速度较慢。此外，应用基于理论冲击效应的校正改善了实验结果。我们的实验证明了花粉采样器显示空气中花粉浓度差异的可能性，并解释了这种不准确的机制。将这些结果应用于花粉采样将有助于了解实际空气中花粉浓度。
Pollen sampling has been performed using various sampling methods around the world. However, the sampling efficiencies of these methods remain unclear. In this study, we compared the sampling efficiency of a Sigma-2 two-layered aerosol sampling inlet and a Hirst-style wind vane inlet to reveal the relationship between sampling efficiency and samplers' physical characteristics. The initial results show a higher sampling efficiency for the former. To further explore this finding, we developed a theory based on 1) continuity equations for pollen grain concentrations and 2) impaction theory. Applying our developed theory to the experimental results revealed that impaction is a significant contributor to the relatively higher sampling efficiency of the two-layered sampling inlet, due to the larger cross-sectional area of the two-layered inlet and slower sampled pollen grain speed within the sampler. Additionally, applying a correction based on the theoretical impaction effects improved the experimental results. Our experiment demonstrated the possibility of a pollen sampler showing discrepancies in airborne pollen concentrations and explained the mechanism of this inaccuracy. The application of these results to pollen sampling will aid understanding of actual airborne pollen concentration.