ABSTRACT
In 2020, Argentina implemented Preventive and Compulsory Social Isolation (ASPO) in the context of the global pandemic caused by the COVID-19 virus. This historical event has led to a decline in economic activities and the movement of the population. Current studies show a decrease in greenhouse gases harmful to health in the atmosphere due to health measures applied to contain the virus. Southwest Buenos Aires (Argentine Republic) is not exempt from these effects. The article aims to analyze the variations of the NO2 levels in pre-pandemic scenarios and during the pandemic. These results indicated a gradual decrease of NO2 related to the decrease in traffic and anthropogenic activities throughout the region, with a significant impact in big cities.