Climatology and trends derived from columnar aerosol measurements in Cluj-Napoca, Romania.

<p>It is well known that in the climate and air quality studies, the monitoring process of aerosols and their temporal evolution is very important as they generate a significant impact on meteorology, air quality, climate, and human and ecosystem health. In this study, we present an overview of aerosol optical and microphysical properties over Cluj-Napoca, Romania- based on more than 12 years of observations from a Cimel sun-photometer operating in the framework of AErosol RObotic NETwork (AERONET) and part of the Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS). This site is located in the north-western part of Romania and contributes to AERONET with sun photometer observation since 2010. As the atmosphere in the region is characterized by a mixture of aerosols from multiple sources: urban/industrial (dominant) biomass burning, Saharan dust, etc., this study aims to present the aerosol trends and the temporal variation of their properties based on long-term observations. The analysis highlighted that the aerosol load over the area is characterized by high inter-annual and seasonal variation of AOD due to variation of local sources and long-range transport. The same variability was observed for the &#197;ngstr&#246;m Exponent, suggesting the presence of aerosols of different sizes. The methods used in this study can be extended to other stations for identifying the long-term variability of aerosols.</p>