The paper presents a discussion on the identification of the source of troposphere NO 2concentration in two cities of Morocco, Casablanca and Rabat. The levels of NO 2during 2015–19 have been used as a baseline to analyse the change in the NO 2level during the COVID-19 induced lockdown in the cities of Morocco. The analysis reveals that the baseline concentration of NO 2during 2015–19 was higher for Casablanca city than Rabat city. Further, the NO 2level during lockdown period has reduced significantly in Casablanca city in comparison with the NO 2levels during 2015-19 and this reduction was higher than that of Rabat city. The primary source for the contribution of troposphere NO 2in Casablanca city was vehicular transport, and a complete lockdown resulted in a significant reduction in NO 2concentration. As Rabat city was not that developed in terms of vehicular load than Casablanca city, the reduction in NO 2concentration was marginal.
Unveiling the causes of reduction in troposphere NO 2in two cities of Morocco during COVID-19 lockdown