Characteristics and source apportionment of PM1 emissions at a roadside station

► We present results from 24 h roadside measurements of PM1 mass and main components. ► Elemental carbon, organic matter, and sulfate are the dominant components. ► All elements related to human health are lower than the guideline values. ► Vehicle exhaust episodes occur during summer. ► Secondary aerosols and incinerator/biomass burning episodes exist during winter.