ABSTRACT
Sphagnum mosses are used for biomonitoring air pollution. In 2019, samples were taken from two peat bogs areas in Germany and two in Slovenia to determine differences in their levels of potentially toxic elements (PTE). The Coronavirus Disease (COVID-19) lockdown caused a global decrease in air pollution. Therefore, we repeated the monitoring in 2020 to see if this was also reflected in moss composition. Despite the variability within bogs and the areas, it is possible to distinguish the degree of air pollution between the two countries. In comparison to 2019, the German mosses have higher contents of almost all elements and the Slovenian are enriched in Cr and Hg in 2020. Comparison of the PTE contents, their ratios to Sc, and the enrichment factors show that the COVID-19 lockdown led to a decrease in long-range pollutants bound to finest particles and increased the influence of local soil dusting. The effect prevailed over lower precipitation in 2020 compared to 2019. Transport and industry continued to contribute significantly to contamination. Sphagnum mosses proved to be good indicators of the spatial and temporal extent of pollution. Even relatively short periods of lower air pollution are reflected in moss PTE contents.