Saharan dust in Central Europe: Impact on particulate matter characteristics in an urban and a natural locality

At the turn of March and April 2024, most of mainland Europe was afflicted by sand dust particles carried by wind flow from the Sahara Desert. As a result, Central Europe experienced an exceptionally high increase in air pollution. In this work, the impact of this Saharan dust event on PM ₁₀ characteristics in an urban and a natural locality in the Czech Republic was investigated. PM ₁₀ concentrations before and during the Saharan dust event were measured using the Beta-Attenuation method. During the Saharan dust event, they were about 6–8 times higher than under normal atmospheric conditions, exceeding WHO guidelines by up to 2 times. A potential effect of terrain and altitude on the local concentrations of Saharan dust was observed. Airborne dust collected before and during the Saharan dust event was then studied using scanning electron microscopy combined with energy-dispersive spectroscopy (single-particle analysis of sizes and elemental composition) and X-ray diffractometry (mineralogical composition). Surprisingly, the particle size distribution was not significantly affected by the Saharan dust advection, but its dependency on the sampling locality was revealed. The dominant mineral in the Saharan dust was calcite, which substantially altered the local PM ₁₀ composition. The studied Saharan dust probably originated from a natural area, as the amount of anthropogenic pollutants detected was negligible. Notably, its carbon content was lower compared with the usual local PM ₁₀ . The elevated PM ₁₀ concentrations appear to be the most relevant risk associated with this Saharan dust event in Central Europe. The transported dust originated from the northern/north-western Sahara – probably from the Atlas region – which was verified by a backward trajectory analysis of air masses.