ABSTRACT
Several measures have been taken to mitigate the effects of the COVID-19 pandemic. In this context, almost all non-essential activities in Morocco have been halted since March 20, 2020. From that date, Morocco announced the lockdown for one month and it was extended until June 10, 2020. The main objective of this paper is to study the effects of the lockdown measures on air quality, by analyzing dust PM2.5, NO2, and O3. The dust PM2.5 analysis was carried out from 2016 to 2020. NO2 and O3 analysis was carried out in 2019 and 2020. This study, which is based on satellite data from TROPOMI Sentinel 5P and MERRA, has shown that Morocco has experienced an improvement in air quality during the lockdown. A significant reduction in surface dust PM2.5 and tropospheric NO2 was observed (-10%,-4%, respectively on average). The total column of ozone recorded a slight increase on average of around 1%. Moreover, we demonstrate that a significant part of particulate pollution and NO2 emissions are incoming mainly from the northern and northern-eastern borders of Morocco. © 2022 Korean Society of Environmental Engineers.
ABSTRACT
On April 20th, 2020, 2,403,410 cases of corona Virus were confirmed globally. This date matches the end of the first strict lockdown in Morocco.. The number of Morocco confirmed cases attended 2990 and 143 deaths were recorded. Due to the pandemic, all avoidable activities in the country were prohibited since the kingdom announced the general lockdown on March 20th, 2020. This study aims at comparing the air quality status, before the pandemic and during the confinement. It was performed in Casablanca and Marrakech from Morocco. The main objective is to show whether COVID-19 compelled lockdown may have saved lives by restraining air pollution than by preventing infection. We used the difference-in-difference and the Theil and Sen non-parametric approaches for univariate time series. We defined the before quarantine period as between February 16th and March 19th and the during quarantine as between the March 20th and April 20th. We assessed changes in air quality during vs. before the quarantine period in 2020 and compared these with corresponding changes in the same lunar calendar periods in 2016-2019. Then we calculated the avoided cause-specific mortality attributable to the decreases in NO2 and PM2.5 based on the concentration-response functions from previous studies. We found that NO2 dropped by -12 µg/m3 in Casablanca and - 7 µg/m3 in Marrakech. PM2·5 dropped by -18 µg/m3 in Casablanca and - 14 µg/m3 in Marrakech. CO dropped by -0.04 mg/m3 in Casablanca and - 0.12 mg/m3 in Marrakech. This air pollution reduction had created human health benefits. It reduced mortality, and saved lives mainly from cardiovascular diseases. Further investigation may be undertaken to explore the reduction in the concentrations of industry-related pollutants.