RESUMO
Parallel reductions in atmospheric aerosols (particulate matter (PM)) and nitrogen dioxide (NO2) accompanied the drastic measures that were adopted to limit the spread of COVID-19. The results of this preliminary study conducted in northern Egypt revealed that ambient PM10, PM2.5, and NO2 levels decreased by 22.8%, 29.3%, and 25.9%, respectively, after the lockdown started on March 13, 2020. These reductions in concentrations significantly (p Ë 0.01) correlated with the decrease in transportation and industrial and other economic activities. Furthermore, PM and NO2 concentrations radically reduced during the full lockdown on Easter, Ramadan, and Eid Al-Fitr. The findings of this study will help the World Health Organization (WHO) and other health regulators to combat COVID-19 in the world. This study is part of an ongoing research related to the current pandemic.