The determination of airborne redox-active compounds (ARC) is essential for monitoring adverse environmental changes and understanding the potential impact on human health. With the exception of relying on the common total organic carbon (TOC) analyzer and dithiothreitol (DTT) assay, there is currently no easy-to-use method for quantitative assessment. Herein, a compatible and easy-to-use colorimetric sensing strategy was developed for on-site ARC quantification. This approach integrated a plasmonic sensing system, where the ARC-induced gold nanoparticles (AuNPs) reduction, localized surface plasmon resonance (LSPR), and the light-mediated photochemistry collaborated to achieve a limit of detection (LOD) at 0.05 μg∙mm⁻² on the filters. Distinguished from the abovementioned methods, the ARC content can be directly determined by in-situ monitoring the colorimetric reaction on the sampling quartz filters (QF) without additional sample pre-treatment. Apart from utilizing the standard benchtop photodetector (e.g., UV–VIS spectrophotometer), the colorimetric images of AuNP@QF samples could also be imaged by a smartphone camera in a sealed box and analyzed through a smartphone-based application to read the RGB (Red, Green, Blue) values for ARC quantification. The good correlation between the results using the spectrophotometer and smartphone validate the applicability of the AuNP sensor. The smartphone-based method was then deployed to test real-world aerosols collected from Zurich, Bern and Rigi and the results of ARC exhibited a positive correlation with that of PM10. With the advantages of low-cost, easy-operation and no need for pre-treatment, this smartphone-based plasmonic system holds great potential for rapid and portable ARC detection and corresponding air quality assessment.

空气中的氧化还原活性化合物 (ARC) 的测定对于监测不利的环境变化和了解对人类健康的潜在影响至关重要。除了依靠常见的总有机碳（TOC）分析仪和二硫苏糖醇（DTT）测定外，目前还没有易于使用的定量评估方法。在此，开发了一种兼容且易于使用的比色传感策略，用于现场 ARC 量化。这种方法集成了一个等离子体传感系统，其中 ARC 诱导的金纳米颗粒 (AuNP) 还原、局部表面等离子体共振 (LSPR) 和光介导的光化学协同实现了 0.05 μg∙mm 的检测限 (LOD) ^{- 2}在过滤器上。与上述方法不同的是，ARC 含量可以通过原位监测采样石英滤光片 (QF) 上的比色反应直接确定，无需额外的样品预处理。除了使用标准的台式光电探测器（例如，UV-VIS 分光光度计）外，AuNP@QF 样品的比色图像还可以通过智能手机相机在密封盒中成像，并通过基于智能手机的应用程序进行分析以读取 RGB（红色, 绿色, 蓝色) 用于 ARC 量化的值。使用分光光度计和智能手机的结果之间的良好相关性验证了 AuNP 传感器的适用性。然后部署基于智能手机的方法来测试从苏黎世、伯尔尼和瑞吉收集的真实气溶胶，ARC 的结果与 PM10 的结果呈正相关。