Efforts to prevent the COVID-19 virus spreading across the globe have included travel restrictions and the closure of workplaces, leading to a significant drop in emissions of primary air pollutants. This provides for a unique opportunity to examine how air pollutant concentrations respond to an abrupt and prolonged reduction. We examine how NO₂ and O₃ have been affected at several urban measurement sites in the UK. We look at the change in NO₂ compared to previous years and the effect on O₃.