RISK OF HIGH PM10 CONCENTRATIONS IN THE YWIEC BASIN DEPENDING ON SYNOPTIC SITUATION

Abstract

This analysis was performed for the ywiec Basin area, located in southern Poland. The topographyof the ywiec Basin is an eminently favourable factor for the stagnation of cool air in the basins andthe formation of the so-called cold stagnation areas, as well as the occurrence of inversion layersinhibiting air mixing. In addition, in the ywiec Basin, the reservoir has a significant influence onthe formation of weather conditions. It favours more frequent formation of local fogs and mists.The study focused on the heating season (6 months) from 2016 to 2021. The analysis coveredwinter seasons at the turn of the year starting from 1 October and ending on 31 March. Duringthis period, for all heating seasons analysed, the average PM10 concentration was 58 g/m3. The2016/2017 heating season proved to be the worst season in aerosanitary terms, with averageconcentrations equalling to 78.4 g/m3. Extreme levels of daily concentrations during thoseseasons were recorded in 2016/2017 (349.0 g/m3) and 2017/2018 (476.2 g/m3). This represented700900% of the limit value for PM10 concentrations. The frequency of exceedances of the dailylimit value D24 for PM10 was high during the heating season, ranging from 83 to 91 days, whichrepresented almost half (46.7%) of the entire season.The next stage of the analysis comprised the evaluation of the levels of daily concentrations (D24)against the background of the baric situation shaping the weather on a given day. The studyjuxtaposed the daily concentrations of PM10 in ywiec with the daily baric situation in the upperVistula river basin. The anticyclonic situation contributed to an increase in PM10 immissionconcentrations in all heating seasons from 2016 to 2021. In all analysed months of the heatingseasons, differences in the average monthly PM10 concentration depending on the baric situationcan be noticed, and the higher the concentration level, the greater this difference is. Similarly, thenumber of days with exceedances of D24 standard for PM10 was several times higher in the periodwhen there was an anticyclone situation. The analysis of the type of air masses showed that thepolar continental air masses were accompanied by the worst aerosanitary