ABSTRACT
This study analyses air quality behavior by considering nitrogen dioxide (NO2) as a reference parameter during atypical conditions associated with the COVID-19 pandemic. NO2 concentrations in 31 departmental capital cities of Colombia (South America) were evaluated during four periods according to government dispositions to face the pandemic: (I) before isolation (normal conditions), (II) mandatory isolation (significant traffic and industrial activity reduction), (III) intelligent isolation (return of some commercial activities), and (IV) selective isolation (Increase of authorized commercial activities). A good fit between ground data and satellite information is observed. Results indicate that most of the cities (45%) present a counterintuitive behavior with concentration increments for Period II with respect to Period I. © 2022, Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma. All rights reserved.