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One of people's greatest concerns about air quality degradation is its impact on human health. This work is a case study that aims to investigate the air quality and the related impact on people's health in a coastal city over the eastern Mediterranean. The analysis proceeded during a low-tourist density period, covering the days from 17 to 27 November 2022. Hourly PM 2.5 , NO 2 and O 3 concentration records from three, mobile, Air Quality Monitoring Systems (AQMS), established in an urban location, port and central area of Rhodes city, are analyzed. To investigate the impact of pollution levels on human health, the Air Quality Health Index (AQHI) is calculated. The daily and diurnal variation of pollutants' concentration and AQHI among the different areas, as well as the relation among the ambient air pollutants and AQHI, are studied. Additionally, to investigate the impact of wind regime on the variation of pollution and AQHI levels, the hourly zonal and meridional wind-speed components, as well as the temperature at 2 m, the dew point temperature at 2 m, and the height of the boundary layer from ERA5 reanalysis, are retrieved for the region of the southeastern Mediterranean. Results show that the highest pollution level occurs in the city center of Rhodes, compared to the rest of the studied locations. In general, the findings do not show exceedances of the pollutants' concentration according to the European Directive 2008/50/EC. Moreover, findings show that in some cases, the health risk is classified from Low to Moderate in terms of AQHI. The analysis indicates that the climate conditions affect the pollutants' concentration due to dispersion, and likely, the atmospheric transport of pollutants. Finally, this work aims to improve the knowledge regarding the air quality of southeastern Greece, promoting the framework for the green and sustainable development of the South Aegean Sea. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Etesian winds represent one of the most stable summer circulation regimes in the Eastern Mediterranean. The Indian Summer Monsoon (ISM) variability and tropical/extra-tropical teleconnections are influencing the Eastern Mediterranean, given that a stronger ISM is often associated with more intense and persistent Etesian winds. The response of Etesian winds to external forcing on interannual and longer time scales, however, is not well understood. Here, for the first time, we investigate responses of Etesian winds to large volcanic eruptions by analysing a blend of model simulations covering the last millennium and reanalysis data over the 20th century. We provide model evidence for significant volcanic signatures, manifested as a robust reduction of the average wind speed in late summer months and the total number of days with Etesian winds. These signatures are attributed to the weakening of the ISM in the post-eruption summer, which reduces large scale subsidence in the Eastern Mediterranean, weakens the Anatolian low, and finally reduces the intensity and persistence of the Etesian winds. We find a stronger sensitivity of Etesian winds to Northern Hemisphere volcanoes, particularly before the 20th century, while for the latest large eruption of Pinatubo, modelled and observed responses are insignificant. Our results could be applied to improve seasonal prediction of wind circulation in the Eastern Mediterranean in the post-eruption summers. [ABSTRACT FROM AUTHOR]

Etesians are north to south direction winds in the lower atmosphere, blowing over the Aegean basin from early summer to early autumn. They are an important circulation component for the East Mediterranean (EMED) area, linked to the subsidence and ascent circulation over EMED and the extended Indian monsoon region, respectively. In this study we investigate the evolution of Etesian days and the associated wind speed (10 m) over the recent past (1979–2005) in simulations from Earth System Models (ESMs) available from the Coupled Model Intercomparison Project Phase 5. Results from this analysis are compared to the ERA‐Interim reanalysis. Moreover, we study the connection of the Etesians to the atmospheric circulation over EMED and the wider Indian monsoon area, in particular over the west Indian summer monsoon (wISM) and the Bay of Bengal (BoB). Our findings suggest that while the ESMs underestimate the wind speed of the Etesians, their frequency and summer cycle are in good agreement to reanalysis. ESMs can accurately represent the summer atmospheric circulation and depict the connection between EMED and Indian summer monsoon (ISM), capturing the link between them. Finally, we highlight here the capability and efficiency of ESMs in representing the climatology of Etesians and related atmospheric circulation. [ABSTRACT FROM AUTHOR]