Effects of the wildfires in August 2021 on the air quality of Athens through a numerical simulation

Abstract

Background. Air quality deteriorates significantly during wildfire events, which poses a risk for the health of affected human populations. The Mediterranean Basin was strongly impacted by wildfires during the 2021 fire season, particularly in Greece. Aims. This work aims at estimating the impact of the Greek wildfires of August 2021 on the air quality in Athens. Methods. The numerical modelling system WRF-APIFLAME-CHIMERE, which comprises a meteorological model, a smoke emissions model and a chemical transport model, was employed in estimating the hourly three-dimensional distribution of particulate matter (PM), CO and O3 concentrations during the wildfires. The performance of the modelling system was evaluated by comparing modelled results with air quality observations and atmospheric optical depth measurements. Key results. Good agreement between measured data and model results was found, with results obtained with a higher-resolution computational grid performing the best. Conclusions. The calculated values indicate concerning hourly and daily levels of air pollution, above the limit values for human health protection, during the analysed days within and around Athens. Implications. The results highlight the importance of implementing a strategy for human health protection during wildfire events affecting populated areas. This modelling approach could be a basis for a smoke forecasting system.