The amount of dust in the air was unprecedented, meteorologists will analyze the reasons

Meteorologists will still analyze the exact reason why the dust reached the lower layers of the atmosphere and its concentrations were high. “Nevertheless, it can be assumed that very good dispersion conditions, stable flow and associated vertical mixing led to the transfer of dust from higher levels to lower levels,” said Vlček.

It was a phenomenon that the ČHMÚ office has not continuously monitored until now, and the ČHMÚ does not even have a suitable mechanism for informing the public in this case. Usually, the transfer of Saharan dust was, from the point of view of ground concentrations, a time-limited phenomenon that affected only part of the territory of the Czech Republic. Vlček also mentioned that the forecast of one of the models used by the ČHMÚ predicted several times lower concentrations.

Even though meteorologists knew about the arrival of the Saharan dust three days in advance and the information was available in public sources, information about the declaration of a smog situation did not reach the public from the ČHMÚ until Saturday. This is issued at the moment when the twelve-hour concentration of dust particles exceeds the value of 100 micrograms per cubic meter at at least half of the stations for the given area and it is clear that the concentration will not fall below this value in the following 24 hours.

“Initially, the situation in the Czech Republic was worst in the southern and eastern parts of the territory, however, relatively quickly, high concentrations were also recorded in the north of the country in the Ústecký, Liberec, Hradec Králové and Pardubice regions. “When predicting the development of the situation, it was important that the Czech Republic was located on the western edge of the area of ​​high concentrations of dust particles, and this resulted in a higher uncertainty of future developments, possibly recorded decreases and re-increases in concentrations, for example in Ostrava,” described Vlček. In terms of the total number of hours when average hourly concentrations exceeded 150 micrograms per cubic meter, the situation was worst in northern Moravia. In Ostrava, the hourly average concentrations reached over 200 micrograms per cubic meter on Monday.

While, for example, in southern Bohemia, concentrations reached values ​​that do not occur even in the winter months with poor scattering conditions, similar concentrations can be measured in Ostrava during this period. However, Vlček emphasized that the toxicity of dust is higher in winter due to its origin. While now it was desert dust, in winter it contains exhaust fumes from transport, industry and local heating plants, which contain a number of cancer-causing substances.

Slovakia, Germany and Switzerland also report an increased concentration of Saharan dust

Foreign