Measurement and source apportionment of atmospheric pollutants are crucial for the assessment of air quality and the implementation of policies for their improvement. In most cases, such measurements use expensive regulatory-grade instruments, which makes it difficult to achieve wide spatial coverage. Low-cost sensors may provide a more affordable alternative, but their capability and reliability in separating distinct sources of particles have not been tested extensively yet. The present study examines the ability of a low-cost optical particle counter (OPC) to identify the sources of particles and conditions that affect particle concentrations at an urban background site in Birmingham, UK. To help evaluate the results, the same analysis is performed on data from a regulatory-grade instrument (SMPS, scanning mobility particle sizer) and compared to the outcomes from the OPC analysis. The analysis of the low-cost sensor data manages to separate periods and atmospheric conditions according to the level of pollution at the site. It also successfully identifies a number of sources for the observed particles, which were also identified using the regulatory-grade instruments. The low-cost sensor, due to the particle size range measured (0.35 to 40 µm), performed rather well in differentiating sources of particles with sizes greater than 1 µm, though its ability to distinguish their diurnal variation, as well as to separate sources of smaller particles, at the site was limited. The current level of source identification demonstrated makes the technique useful for background site studies, where larger particles with smaller temporal variations are of significant importance. This study highlights the current capability of low-cost sensors in source identification and differentiation using clustering approaches. Future directions towards particulate matter source apportionment using low-cost OPCs are highlighted.

中文翻译：

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使用监管仪器和低成本传感器评估城市背景站点的粒子来源——一项比较研究

大气污染物的测量和来源分配对于评估空气质量和实施改善空气质量的政策至关重要。在大多数情况下，此类测量使用昂贵的监管级仪器，这使得难以实现广泛的空间覆盖。低成本传感器可能提供更实惠的替代方案，但它们在分离不同颗粒来源方面的能力和可靠性尚未经过广泛测试。本研究考察了低成本光学粒子计数器 (OPC) 识别粒子来源和影响英国伯明翰城市背景站点粒子浓度的条件的能力。为了帮助评估结果，对来自监管级仪器 (SMPS、扫描迁移率粒度仪）并与 OPC 分析的结果进行比较。低成本传感器数据的分析可以根据现场的污染水平来划分时期和大气条件。它还成功地识别了观察到的粒子的许多来源，这些来源也使用监管级仪器进行了识别。由于测量的粒径范围（0.35 至 40 µ m)，在区分尺寸大于 1 µm的颗粒来源方面表现相当好 ，尽管它在现场区分其昼夜变化以及分离较小颗粒来源的能力有限。当前显示的源识别水平使该技术可用于背景站点研究，其中具有较小时间变化的较大粒子具有重要意义。这项研究强调了低成本传感器在使用聚类方法进行源识别和区分方面的当前能力。强调了使用低成本 OPC 进行颗粒物源分配的未来方向。