Abstract Satellite HCHO data are widely used as a reliable proxy of non-methane volatile organic compounds (NMVOCs) to constrain underlying emissions and chemistry. Here, we examine global significant changes in HCHO columns at the early stage of the COVID-19 pandemic (January–April 2020) compared with the same period in 2019 with observations from the TROPOspheric Monitoring Instrument (TROPOMI). HCHO columns decline (11.0\%) in the Northern China Plain (NCP) because of a combination of meteorological impacts, lower HCHO yields as NOx emission plunges (by 36.0\%), and reduced NMVOC emissions (by 15.0\%) resulting from the lockdown. HCHO columns change near Beijing (+8.4\%) due mainly to elevated hydroxyl radical as NOx emission decreases in a NOx-saturated regime. HCHO columns change in Australia (+17.5\%), Northeastern Myanmar of Southeast Asia (+14.9\%), Central Africa (+7.8\%), and Central America (+18.9\%), consistent with fire activities. Our work also points to other changes related to temperature and meteorological variations.