The fine particles from the Po Valley have also arrived in the Aosta Valley
February 23, 2024 – For several weeks throughout the Po Valley they persist high concentrations of fine particles (PM), which exceeded the established limits and alarmed citizens and institutions. As reported in the media, the phenomenon is clearly visible even from space. In the afternoon of Wednesday 21 February, our Air Quality stations have detected a sudden increase of the concentrations of powders also in Valle d'Aosta. These particles were transported from the Po Valley to the Alpine regions by atmospheric circulation.
In the graph, the PM concentrations measured at the Donnas station on 21 and 22 February show a clear increase in dust starting from 12pm on February 21st (highlighted with the red arrow; the four lines represent the 4 particle sizes of PM, from the fine fraction - in red - to the coarser one - in purple).
There are concentrations kept high until 17pm of the following day, when the rainfall they started leach dust into the atmosphere.
This phenomenon resulted in the overcoming of the daily limit for PM10 of 50 µg/m³ for the 22 February 2024 only in Donnas station, mostly affected by the transport of Po Valley air masses and subsequently reached by precipitation.
In all the other stations in the region, affected by rainfall since the morning, the concentrations did not exceed the daily limit.
