X- ray absorption spectroscopy analysis of aerosol particles during summer and winter in Krakow, Poland

Airborne fine particulate matter (PM_2.5) pollution decreased during last decade in Krakow, Poland. X-Ray Absorption Near Edge Structure (XANES) technique at ASTRA beamline of SOLARIS Synchrotron (Krakow, Poland) has been used to study of 8 aerosol samples (PM_2.5) collected in Krakow during summer and winter 2018/2019 and 2020/2021 at K absorption edges of sulphur, chlorine, potassium, iron and zinc. Samples of PM_2.5 collected in summer contain sulphur mostly as sulphates. On the other hand, samples collected in winter additionally contain bisulphates, sulphides and organic sulphur. KHSO₄ and K₂SO₄ are the primary contributors to potassium pollution in winter. Iron phases of Fe^{+ 3} and Fe^{+ 2} oxidation states (FeSO₄, Fe₂O₃ and FeOOH) are present in the samples of PM_2.5. Main zinc containing phases present in PM_2.5 samples are ZnSO_4, ZnS and ZnO. Such advanced unique technique as XANES applied for PM_2.5 research can be useful for preparing a program reducing the air pollution level of the city. The study also has a broad aspect, it helps to clarify the kind of chemical compounds present in particulate matter.