Drone-Based Aerosol Profiling: Calibration Using an In Situ Multi-Sensor System

Aerosol profile measurements are crucial for validating and improving atmospheric models, satellite remote sensing algorithms, and regional dynamic models that consider the fine vertical structure of boundary layer dynamics. The boundary layer, where the atmosphere interacts with the Earth’s surface, is characterized by rapid changes in temperature, humidity, and turbulence. These thermodynamic conditions influence aerosols’ hygroscopic growth, mixing, and their roles in global atmospheric processes such as cloud formation and radiative transfer. The applying of unmanned aerial vehicles (UAVs) offers the potential for high-resolution in-situ profiling of aerosol parameters, enabling the capture of fine-scale variations often missed by traditional methods such as satellite observations or ground-based instruments. Since aerosols in the boundary layer are rarely uniformly distributed, their spatial heterogeneity significantly impacts air quality assessments and pollutant transport modeling.

In coastal regions, aerosol PM measurements are particularly valuable for evaluating the combined effects of marine and terrestrial emissions on air quality, ecosystem health, and nearby populations. However, deploying rotary UAVs as air quality sensor platforms presents unique challenges. The turbulence generated by UAV propellers can alter the sampled aerosol concentrations, potentially leading to quasi-systematic inaccuracies. Addressing this issue requires careful calibration of UAV-based sensors in the field.

Given study presents the results of vertical aerosol profile measurements, focusing on PM₁, PM_2.5, and PM₁₀ concentrations, conducted during a short measurement campaign above the sea surface near Hel (54°44'25.9" N, 18°34'02.5" E), Poland. Data were collected using an OPC-N3 sensor mounted on a UAV at altitudes ranging from 5 to 120 m. Calibration of the drone-based measurements was performed using the specially designed Integrated Aerosol Monitoring Unit (IAMU), which houses three aerosol sensors (SPS30, OPC-N3, and OPS 3330) within a single enclosure [1]. All IAMU sensors as well as drone-based sensor are sensitive to hygroscopic growth of aerosol because of the absence of sample drying. However, the calibration approach formulated in [1] allows for approximating aerosol grow factor coefficient. This assessment was supported by auxiliary observations from a nephelometer Aurora 4000, Sun photometer and meteorological station. A calibration technique is proposed for the OPC-N3 sensor, incorporating synchronous IAMU data and accounting for aerodynamic losses in the sampling inlet tubes.

• Bruchkouski, I.; Szkop, A.; Wink, J.; Szymkowska, J.; Pietruczuk, A. Multi-Sensor Instrument for Aerosol In Situ Measurements. Atmosphere 2025, 16, 42. https://doi.org/10.3390/atmos16010042