Unveiling the causes of reduction in troposphere NO2 in two cities of Morocco during COVID-19 lockdown

Abstract

The paper presents a discussion on the identification of the source of troposphere NO2 concentration in two cities of Morocco, Casablanca and Rabat. The levels of NO2 during 2015–19 have been used as a baseline to analyse the change in the NO2 level during the COVID-19 induced lockdown in the cities of Morocco. The analysis reveals that the baseline concentration of NO2 during 2015–19 was higher for Casablanca city than Rabat city. Further, the NO2 level during lockdown period has reduced significantly in Casablanca city in comparison with the NO2 levels during 2015-19 and this reduction was higher than that of Rabat city. The primary source for the contribution of troposphere NO2 in Casablanca city was vehicular transport, and a complete lockdown resulted in a significant reduction in NO2 concentration. As Rabat city was not that developed in terms of vehicular load than Casablanca city, the reduction in NO2 concentration was marginal.