Comparison of online (Xact) and offline (ICP-MS) measurements for trace elements in particulate matter across the EU

Elemental composition and concentration of trace elements in particulate matter (PM) are used for source apportionment due to their toxic effects on human health (Yang, 2022). Measurement of trace elements can be performed with online or offline instruments. The most used online instrument is Xact 625i (Cooper Sci., an XRF spectrometer) (Furger, 2017). In case of offline measurements, ICP-MS or ICP-OES methods are mostly used, followed by benchtop X-ray diffraction (XRD) instruments (Brown, 2010). We show correlation between offline ICP-MS/ICP-OES and online XRF methods for trace elements, performed on measurements from 4 different sites across Europe: Deskle, a small Alpine village in Western Slovenia (SLO) with the proximity of cement industry and dominant wood-burning for heating