Air Quality Health Index and Discomfort conditions in a heatwave episode on the island of Rhodes in July 2024

Climate conditions in combination with the concentration of pollutants increase human health stress and exacerbate systemic diseases. The city of Rhodes is a desirable tourist destination that is located in a sensitive climate region of the southeastern Aegean Sea in the Mediterranean. In this work, hourly recordings from a mobile air quality monitoring system which is located in an urban area of Rhodes city were employed in order to measure the concentration of regulated pollutants (SO2, NO2, O3, PM10 and PM2.5) and meteorological factors (pressure, temperature and relative humidity). The Air Quality Health Index (AQHI) and Discomfort Index (DI) were calculated to study the impact of air quality and meteorological conditions on human health. The analysis was conducted during a hot summer period, from 29 June to 14 July 2024. During the second half of the studied period, a heatwave episode occurred, affecting the bioclimatic conditions over the city. The results show that despite the fact that the concentration of pollutants was lower than the pollutant thresholds (according to Directive 2008/50/EC), the AQHI and DI conditions degraded significantly over the heatwave days. In particular, the AQHI suggested a reduction in outdoor activities and the DI indicated that most of the population suffered discomfort. The AQHI and DI simultaneously increased during the days of the heatwave episode, showing a possible negative synergy for the health risk. Finally, both the day maximum and night minimum temperatures were increased (about 0.8 and 0.6 °C, respectively) during the heatwave days as compared to the whole studied period.