Variability of Aerosol Properties Using AERONET Retrievals and Relation between Aerosol Optical Depth and PM Levels at Ioannina, Greece 2022.

In this study, we try to characterize local aerosols over the city of Ioannina for the first time using continuous AERONET CIMEL Sun-Sky spectral photometer measurements. The instrument, which belongs to the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, was installed in 2022 at the University of Ioannina and operated for a 5-month period from 23 February to 30 June 2022. Based on its measurements and retrievals, we investigate aerosol optical properties on a monthly, daily and hourly mean basis and reveal relationships between Aerosol Optical Depth (AOD) and local particulate matter (PM). It is found that the 5-month mean AOD is 0.17, from which 0.08 is ascribed to fine-mode and 0.09 to coarse-mode aerosols, while the corresponding mean Angstrom Exponent is 0.95. The total PM, PM₁₀ and PM_2.5 concentrations for the same period are equal to 32.51, 22.39 and 11.40 µg/m³, respectively. The correlation coefficient between PM₁₀ and AOD_500nm is equal to 0.79, and the one between the PM_2.5/PM₁₀ ratio and the Fine-Mode Fraction of AOD is equal to 0.76. Events of episodic fine and coarse aerosol conditions, which took place during the study period, are also analyzed using AERONET Volume Size Distribution (VSD) inversion products, along with back trajectories obtained with the NOAA's HYSPLIT model, to assure the origin of the particles. [ABSTRACT FROM AUTHOR]