The Air Quality and Influence of Etesians on Pollution Levels in the City of Rhodes: The Case of July 2022

Abstract

In July 2022, strong and high-frequency northern sector winds blew over the Aegean Sea. The low tropospheric circulation in combination with air quality and human comfort is of great importance for the climate and human health. This study investigates the variation in pollutants’ concentrations (PM10, NO2, O3 and SO2), meteorological factors (temperature, relative humidity, wind speed and direction) and the discomfort index in the city of Rhodes during July 2022. Additionally, the impact of Etesians on pollution levels is studied. The strength of the Etesian flow is quantified by calculating a statistical index that takes the July pressure gradient (ΔP) over the Aegean Sea into consideration. For the analysis, pollutants’ concentration recordings from a mobile air-quality-monitoring system during July 2022 and mean sea level pressure (MSLP) data from ERA5 reanalysis during July for the period from 1980 to 2022 are analyzed. The results indicate that traffic affects the pollution level although the pollution limits, according to the European directive for air quality (2008/50/EC), are not exceeded. The findings also reveal an increase in ΔP, about 1.8 hPa, during 2022 compared to the period from 1980 to 2022 and the dipole of high (over Balkans) and low (over eastern Mediterranean) pressure centers also strengthens, leading to stronger winds over the Aegean Sea. The ΔP is strongly correlated (0.8) to the first principal component of MSLP over the eastern Mediterranean. Finally, this study shows that the Etesian flow tends to reduce the concentration of PM10, NO2 and O3, and improving the air quality in the city of Rhodes.

Keywords

• air quality
• pollutants
• discomfort index
• Etesian flow
• low tropospheric circulation
• eastern Mediterranean