The aim of this project is to perform simulations EMEP MSC-W chemical transport model (https://github.com/metno/emep-ctm) in two research projects. The first aims to assess the effects of the IMO's NOx regulations in the Baltic Sea and the North Sea on air quality and health in Swedish port cities, using Gothenburg as an example. It will also investigate effects of non-compliance with the legislation and if regional and local measures, such as for example Clean Shipping Index and on-shore electricity in ports, can accelerate the reduction of NOx emissions from shipping in the region. Both the absolute and especially the relative contribution of the shipping sector to the burden of emissions of NOx in Europe have been increasing, and in 2020 the share of NOx emissions from shipping on seas surrounding the continent corresponded to 50% of total emissions from all land sources in the EU. In this project we will use scenarios and dispersion modelling to analyse: -What is the effect on health risks if the emissions are higher than anticipated in the NOx-legislation, as has been observed for a large number of ships? -What is the effect of policy measures aimed at reducing the NOx emissions? A set of scenarios downscaled to the region around Gothenburg will be developed and used in a city-scale model to investigate impacts of the different measures on the air pollution situation in the city for 2030 and 2040. The project builds on results from the Horizon2020 projects SCIPPER and EMERGE and is a research project funded by the Swedish Transport Administration. The second research project aims to assess the effects of emissions from low carbon fuels and technologies mitigating emissions of greenhouse gases in hard-to-electrify (HtE) transport sectors aviation, shipping, heavy-duty on-road and non-road mobile machinery in Horizon Europe project REALCHEM. The project will observe emissions from various fuels and engines under real-life conditions, model their effects on air quality and assess impacts on human health, focusing on the most important new technologies. The aim is to produce guidance and technology packages for cleaner transport in terms of health effects and climate impacts. Future technological trajectories with adaptation of low-carbon fuels in the HtE transport modes will be constructed and emissions of both regulated and non-regulated emerging air pollutants will be estimated. The project resources will be used to model impacts of emissions in the different trajectories on air quality and climate with EMEP MSC-W model at both European and regional (Swedish West coast) scale.