Mass concentration and elemental content of PM10 during painting/sketching activities in a university classroomMass concentration and elemental content of PM10 during painting/sketching activities in a university classroom Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2021-05-202021enPM10 concentration and its elemental content were measured inside a university classroom where painting and sketching activities took place. The primary goal was to investigate the impact of these activities to (1) indoor PM10 concentrations, (2) identify PM10 levels in the presence/absence of the activities and (3) investigate the corresponding impact on its elemental content. As such, indoor online measurements and 24-h gravimetric measurements took place at short-term fixed periods. Outdoor PM10 concentrations were also available. It was found that PM10 levels were substantially increased during the occupied hours with average PM10 during activity ranged between 19 and 171 μg/m3, whereas during background periods it ranged between 12 and 66 μg/m3. Moreover, indoor concentrations during the activity were usually higher compared to outdoor levels, but the opposite behavior was found for background periods. Regarding the elemental content, positive correlations of heavy metals (Cu, Zn, Pb, Ba) found predominantly in the coarser fraction were associated with the use of painting powders. On the other hand, metals like Cr, Mn, Fe and Ni were primarily associated with anthropogenic sources, while the crustal origin of Ti, Mg and Al dominated indoors for particles > 1 μm. Other correlations between elements in the submicron fraction suggested origin from soil and anthropogenic sources as well as aged painting-originated particles. In summary, the present study demonstrated the significant impact of painting/sketching activities to indoor PM10 levels. Direct emissions from the use of powders as well as resuspension activities of the occupants were identified as the major indoor sources that provoked elevated concentrations.http://creativecommons.org/licenses/by/4.0/International Journal of Environmental Science and Technology1851061-1072 Chatoutsidou Sofia-Eirini Χατουτσιδου Σοφια-Ειρηνη Pantelaki Christina Παντελακη Χριστινα Kopanakis Ilias Κοπανακης Ηλιας Andreadakis Dimitrios Ανδρεαδακης Δημητριος Petroulakis Stylianos Πετρουλακης Στυλιανος Lazaridis Michail Λαζαριδης Μιχαηλ Springer Nature PM10 Elemental concentration Painting Sketching Indoor activities