The total arsenic concentration and the concentration of its individual species were monitored in the PM₁₀ fraction of urban aerosol sampled in the city of Brno, located in central Europe, Czech Republic.

Monitoring was carried out at three sites within the city in order to compare the effect of their different nature on arsenic concentrations and the abundance of individual arsenic species. The latter was also evaluated from a seasonal perspective, with sampling repeated in two campaigns, in autumn 2022 and winter 2023. To gain a deeper understanding of the issue, a complementary analysis of total arsenic in different PM_x fractions was performed.

The analysis of total arsenic concentration in samples mineralized with nitric acid and hydrogen peroxide was performed using ICP-MS/MS technique. Concentrations of individual arsenic species (arsenite As³⁺, arsenate As⁵⁺, monomethylarsonate MMA, dimethylarsenite DMA and trimethylarsine oxide TMAO) in samples leached into water were carried out using a combined HPLC-ICP-MS/MS technique.

The results clearly showed a seasonal trend in the abundance of arsenic species, probably caused by biomethylation processes. However, the spatial effect within the city was statistically inconclusive. The results of the complementary analysis of total arsenic concentrations in PM_x suggest that arsenic most likely originated from local emission sources such as industrial activity and heating in winter.