Considering the growing transport demand and dependence on oil, collective and immediate actions must be taken to abate emissions and mitigate their environmental and health impacts. Very fine particles emissions, and the formation of secondary aerosols through atmospheric processing, are believed to be the pollutant with the greatest public health impact, even if there is a major knowledge gap concerning their atmospheric behaviour (e.g. mechanism/contribution to smog episodes). AEROSOLS is a 36-months timely, ambitious, and interdisciplinary project with aim to define robust and transparent measurement and modelling methodologies to quantify the currently disregarded volatile/semi-volatile (V/S-V) primary and secondary emissions, and their associated risks. Furthermore, technological and legislative monitoring/abating mechanisms will be proposed to control these emissions in order to help improve air quality and public health. This will be achieved by: - quantifying V/S-V emissions formation, abatement, and dynamics within the vehicle system under real-driving-emissions (RDE) testing conditions on roads and in labs utilising innovative instrumentations and methodologies; - characterising secondary aerosol formation and atmospheric evolution mechanisms employing advanced instrumentations (e.g. for particles as small as 1nm), methodologies, and modelling to provide scientific evidence of the precursors’ role; - categorising (‘taxonomising’) and prioritising (assisted by Artificial Intelligence) primary and secondary emissions compounds based on their health impact (by employing in vitro/vivo testing), environmental/social life-cycle-assessment, and risk. Advocacy information will be provided to the stakeholders and legislation/policy makers and proposals will be made for improving the standards/regulations, and consequently the air quality. The support of stakeholders and partners will accelerate the transition to a cleaner and climate-neutral society/economy.