It is unsurprising that process steps I and III show similar impact contributions to the overall LCIA results, as both these steps involve ozonolysis reactions and feature the same reaction and separation technologies. To provide systematic guidance for the optimisation of individual process steps, the key impact contributing activities within steps I -VI were determined within a more granular hotspot analysis. The results presented in Figure show the relative impact contributions of the main operational activities within steps I and IV; results for the remaining process steps are shown in SI Section S8.4.