A Field-Based Evaluation of Low-Cost Pollen Sensors for their Applicability To Asian Dust Detection

Public concern is growing over the impacts of Asian dust on air quality, climate, and human health, as well as over its potential synergistic effects with other particles, which remain unresolved. However, conventional long-term direct observations are declining due to constraints on human resources, highlighting the need for alternative monitoring approaches. In this study, we developed and validated a Dust Proxy based on particle size and polarization measurements using a low-cost pollen sensor (PS3). The proxy was identified and evaluated through field measurements conducted in Tsukuba, Japan, from April to July 2024, in comparison with research-grade in-situ observations, lidar data, and meteorological reports. The proxy was defined based on the predominance of finer and sub-spherical particles detected by the PS3 during dust events. This proxy correlated more strongly with dust concentrations than total particles, and periods exceeding 70 particles h-1 captured not only large-scale dust transport events but also smaller events identified in research-based observations. Overall, the approach proposes a cost-effective and scalable method to complement existing dust observation networks. Furthermore, simultaneous monitoring of pollen and dust on the same device can provide opportunities to conveniently monitor environmental and health impacts associated with their interactions.