The capability of trapping and collecting airborne particulate matter is of great applications in the fields of environmental engineering, healthcare systems, energy engineering, and so forth. In this work, we show a facile strategy of trapping and collecting airborne particulate matter by a simple and compact ultrasonic device system. In this device, a radiation plate is bonded with a Langevin transducer for generating circular standing flexural waves (CSFWs) in the plate. Under the excitation of the CSFWs in the radiation plate, an acoustic field and an acoustic streaming field can be induced in the air gap formed by the radiation plate and a sampling plate. Through numerical simulations, we find that the multiple acoustic streaming vortices symmetric about the central axis in the air gap are responsible for trapping and collecting airborne particulate matter onto the sampling plate, while acoustic radiation force contributes little. Also, it is numerically found and experimentally verified that the resonant acoustic field and the accompanying acoustic streaming field can be tuned by varying the thickness of air gap. Through experimentation, we investigate and clarify the dependency of collection performance on parameters such as the air gap thickness and radius, sonication time, driving voltage, and the angle between the radiation plate and the sampling plate. Due to its contactless and mild handling attributes, our ultrasonic airborne particulate matter sampler can circumvent the clogging and secondary pollution issues and ensure device reusability and little damage to samples compared with other airborne particulate matter processing methods.

捕集和收集空气中颗粒物的能力在环境工程、医疗保健系统、能源工程等领域有着重要的应用。在这项工作中，我们展示了一种通过简单紧凑的超声波设备系统捕获和收集空气中颗粒物的简便策略。在该设备中，辐射板与朗之万换能器结合，用于在辐射板中产生圆形驻波 (CSFW)。在辐射板中CSFW的激发下，可以在辐射板与采样板形成的气隙中感应出声场和声流场。通过数值模拟，我们发现气隙中关于中心轴对称的多个声流涡流负责将空气中的颗粒物捕获和收集到采样板上，而声辐射力贡献很小。此外，数值发现和实验验证了共振声场和伴随的声流场可以通过改变气隙的厚度来调整。通过实验，我们研究并阐明了收集性能对气隙厚度和半径、超声处理时间、驱动电压以及辐射板和采样板之间的角度等参数的依赖性。由于其非接触和温和的处理特性，