A significant part of 2020, Nanoconsult has spent on composing a white paper on the health impact of microplastic particles. For this effort a read-across approach was taken to use current know-how and paradigms developed in other particle area’s such as PSLT, nanomaterials and ambient PM. The final report was now delivered to ICCA and will be submitted for publication asap. Form our analysis it is clear that using read-across as an approach to use and extrapolate existing know-how from particle domains PSLT, ambient PM and organic fibres, has both fundamental and practical limitations. First of all, read-across has barely been explored to the level of groups of (particle) substances, and secondly the data gaps between particle domains are too large for validating an overarching mode of action such as the inflammatory response in the lung that characterizes all particle domains. Although none of the particle domains is really adequate, the best candidate for read-across is provided by the robust worldwide dataset of ambient PM. However, a large number the data-gaps regarding exposure measurements and hazard testing at relevant levels need to be closed. More data on MPs content in PM10 samples are needed to fill the first data gap for using PM data in MPs health impact assessment.