COVID-19 national lockdown in morocco: Impacts on air quality and public health

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 PM_2.5 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. PM_2·5 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.