Massive Saharan Dust Oubreak in Central Europe - Analysis of Potential Factors and Impacts

The article assesses the massive transport of dust from the Sahara desert in the period between March and April 2024 in the Czech Republic. This event caused the declaration of smog situations due to high PM ₁₀ concentrations and affected the entire territory of the Czech Republic. The presence of Saharan dust in the Czech Republic is not unusual, but this was the first time that such high PM ₁₀ concentrations on such a large scale have been recorded near ground. The purpose of this paper is to analyze the factors that led to this situation. This extraordinary episode was caused by a combination of several meteorological and topographic factors. There was a massive and relatively constant uplift of dust plumes from the Hautes Plaines area (part of the Atlas Mountains in northern Africa), combined with strong downslope winds behind mountain barriers in Central Europe, mainly the Alps. The steady, very good dispersion conditions with prevailing SW wind direction of dry air masses at higher speeds, played a significant role. The combination of factors also allowed high concentrations of Saharan dust to permeate to low altitudes towards the surface through temperature inversions or even aided its dispersion.The analyses in this article provide a basis for improving public awareness and informing state authorities. The assessment could serve as a basis for amending rules relating to the issuing of warnings and smog alerts in the Czech Republic. Unlike the existing rules, which only considered anthropogenic sources in case of PM ₁₀ smog situations, particularly industrial sources, the new rules should also take into account the possible influence of natural sources.