This project will determine the dew point of water, or "water solubility", in impure CO2 mixtures (e.g. containing N2 and H2). At present, key data for defining water levels have not been determined. The data are important because liquid water is highly acidic in the presence of excess CO2; this acidity can be increased by trace amounts of SO2 and H2S and acidity will greatly accelerate corrosion. This research will provide the first accurate data for CO2 transportation systems, which can be used to develop accurate equations of state and define more robust pipeline specifications. These in turn can be applied to inform cost benefit analyses on the additional costs on the pipeline material and construction balanced against the cost of purification and the needs of safety. The research will provide critical physical property data to enable the safe and cost effective transportation of CO2. Grant number: UKCCSRC-C1-21.