Atmospheric aerosol from on-road transport in Europe: The role of different vehicle types

On-road vehicles are an important source of atmospheric particulate matter (PM), producing both primary aerosol and gas-phase precursors, which react in the atmosphere and lead to the formation of secondary aerosol. Over the past 50 years, the emissions from the exhaust of passenger cars have been thoroughly studied, on the contrary, other on-road vehicles, like mopeds, buses, and heavy-duty vehicles, have received less attention. Moreover, as regulatory measures reduce the concentrations of primary aerosol emitted from on-road vehicles, the significance of the gas-phase precursors increases. The aim of this study is to assess both the overall effect of different on-road vehicle types on particle mass concentrations over Europe, as well as the specific role of volatile and intermediate volatility organic compounds to the formation of secondary organic aerosol (SOA). To achieve this, the results of the EASVOLEE (Effects on Air Quality of Semi-VOLatile Engine Emissions) emission characterization campaigns were used to update PMCAMx inputs and parameterizations. The three-dimensional chemical transport model was used to simulate a summer month (July 2019) in Europe. The contribution of different vehicle types to the total PM_2.5 and to the concentrations of primary and secondary OA. The model simulations provide insights about the significance of specific volatile and intermediated volatility compounds emitted from on-road vehicles over Europe.