Emissions of nitrogen oxides (NO_x) to the atmosphere are an ongoing air quality issue. This study directly measures emissions of NO_x and carbon dioxide from a tall tower in central London during the coronavirus pandemic. It was found that transport NO_x emissions had reduced by >73 % since 2017 as a result of air quality policy and reduced congestion during coronavirus restrictions. During this period, central London was thought to be dominated by point-source heat and power generation emissions.