Investigating Pollutant-Meteorology Interactions In Urban Surface Layer Through UAV-Based Vertical Profiling

Understanding the vertical structure of aerosols near the surface is crucial for enhancing exposure assessment, validating air quality models, and characterizing boundary layer processes at fine spatial scales, as pollutant level varies significantly due to complex interactions between emissions and local atmospheric conditions. However, most monitoring networks depend on surface stations that cannot detect altitude-related changes within the lowest tens of meters. This range is significant to human exposure and pollutant transformations. This study presents early results from a UAV-based vertical profiling system designed for high-resolution measurements of PM₂.₅ and key meteorological parameters. A multirotor drone equipped with a custom sensor module, including a NOVA-SD laser-scattering PM₂.₅ sensor, a Bosch BME280 sensor for measuring barometric pressure, temperature, and relative humidity, and an STM32 Microcontroller for onboard data logging, was used for two vertical profiling flights. The UAV ascended up to 35 m above ground level, collecting resolution measurements for all mentioned variables at each second. Over both flights, more than 1,500 data points were gathered. The profiles show expected thermodynamic behavior, that is, temperature and pressure decrease with altitude, while relative humidity increases in the upper part of the measured layer. PM₂.₅ levels were generally low but showed noticeable altitude-related variations. A mid-altitude increase appeared consistently in both flights, indicating a shallow aerosol layer rather than sensor noise. These initial findings highlight the potential of UAV-based sensing to detect fine-scale stratification that surface monitors miss. The expanded dataset will help create a validated UAV-based approach that complements traditional monitoring networks and provides better insight into urban boundary-layer air quality.