Environmental episode in Barcelona due to a Saharan dust outbreak

Abstract

Between 23/02/2021 and 26/02/2021, the Generalitat de Catalunya declared an environmental episode in the Barcelona area due to a Saharan dust outbreak. For its depiction, PM10 concentration measurements and ceilometer data from Palau Reial station, along with backward air mass trajectories, have been analyzed. The PM10 concentration in Palau Reial exceeded 50 μg/m3 for about 8 h on 23/02/2021. This threshold was surpassed and sustained for several days in other stations belonging to the Zona de Protecci´o Especial, leading to the declaration of the environmental episode. These findings align with the ceilometer data, which revealed a significant aerosol presence near ground level through the planetary boundary layer. Its thickness was below 750 m most of the time. Additionally, the course and height of the air masses confirm the long-range transport of air originating from Saharan regions, as well as the key role of the Atlas mountain range in lifting dust into the free troposphere in this episode