As part of WP3 the Trop-ClOC team measured HCl and other inorganic chlorine compounds at the Manchester air quality supersite during the summer of 2021 and winter of 2022. Collaborating with the UKRI funded OSCA project meant supporting observations of a wide range of gas and particulate phase measurements were made simultaneously, enabling a complete atmospheric reactive chlorine budget analysis in this periodically marine influenced urban environment.