key: cord-0689338-h201j3qs
authors: khomsi, k.; Najmi, H.; Amghar, H.; Chelhaoui, Y.; Souhaili, Z.
title: COVID-19 national lockdown in Morocco: impacts on air quality and public health
date: 2020-07-17
journal: nan
DOI: 10.1101/2020.07.05.20146589
sha: 9175de271011994699a34fc098976bd6af721216
doc_id: 689338
cord_uid: h201j3qs

On the 20th April 2020, the end date of the first strict lockdown period in Morocco, 2 403 410 cases of the corona Virus were confirmed globally. The number of Morocco confirmed cases attended 2990, while 12 746 were suspected and 143 deaths were recorded. Due to the pandemic of coronavirus disease 2019 worldwide and in Morocco, almost all avoidable activities in the country were prohibited since the kingdom announced activities reduction on March 16, 2020 and then general lockdown with reduced industrial activities on March 20, 2020. This study aims at comparing the air quality status in Casablanca and Marrakech, two large cities from Morocco, before the pandemic and during the lockdown situation to show whether COVID-19 compelled-anthropogenic activities lockdown may have saved lives by restraining ambient air pollution than by preventing infection. We found that, during the quarantine, NO2 dropped by -12 g/m3 in Casablanca and -7 g/m3 in Marrakech. PM2.5 dropped by -18 g/m3 in Casablanca and -14 g/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 and had reduced mortality and saved lives mainly from cardiovascular diseases.

Wuhan in China on the 31 st December 2019 (Khan and Naushad, 2020). On the 20 th April 2020, 29 COVID-19 has led to more than 165 000 deaths worldwide with a global mortality rate of 6.8% 30 (WHO, 2020a) . Due to the contagious nature of COVID-19, most countries declared the lockdown, 31 hence businesses and industrial activities decreased, global air travel reduced and cars and trucks 32 stayed off the roads (Isaifan, 2020; Martins, 2020; Wang et al., 2020) . 33

Morocco reported the first COVID-19 case on the 2 nd March 2020, 39 cases, and 1 death 34 followed. Then the government announced the obligation of physical distancing and border 35 closures on the 16 th March 2020 and gathering places closed. The lockdown followed on the 20 th 36

March 2020. Since then, the unofficial transit going in and out of Moroccan cities was shut down, 37 most transportation was prohibited and almost all avoidable outdoor human activities stopped all 38 around the country. On the 20 th April 2020, the end date of the first strict lockdown period, Morocco 39 announced 2990 confirmed cases and 143 deaths, thus a mortality rate of 4.8% (Ministry of Health, 40 USA (Newburger, 2020) . In the city of Salé in Morocco, PM10 and NO2 concentrations dropped 51 respectively by 75% and 96% during the period between the 11 th March and the 2 nd April 2020 52 (Otmani et al., 2020) . 53

According to the World Health Organization (WHO), 4.2 million deaths have been caused by 54 ambient air pollution worldwide in 2016. The latter is estimated to cause about 29% of lung cancer 55 deaths, 24% of stroke deaths, 25% of heart disease deaths, and 43% of other lung diseases. 56

Moreover, air pollution has attributed to 26% of respiratory infection deaths, 25% of chronic 57 obstructive pulmonary disease (COPD) deaths, and about 17% of ischemic heart disease and stroke. 58

It is noteworthy that chronic respiratory and cardiovascular diseases may be linked to COVID-19 59 as the death rate caused by the virus is higher among those with these diseases (Isaifan, 2020 ; 60 WHO, 2020b). As for Morocco, each year more than 13,000 deaths is due to air pollution. This 61 represents about 7% of all deaths thus the 8 th largest mortality risk factor. According to the global 62 report "Toxic Air: The Price of Fossil Fuels" of the international NGO Greenpeace MENA, 63 annually deaths due to air quality degradation in Morocco is estimated at 5,100 in 2018 (Farrow, 64 A., Miller, K.A. & Myllyvirta, 2020).

Obviously, COVID-19 is a treat for public health, nevertheless, the accompanying lockdown 66 measures, instigating improved air quality, may have positive effects on human life and well-being. 67

For instance, Chen et. al estimate that improved air quality in China, during the quarantine period, 68 avoided a total of 8911 NO2-related deaths and 3214 PM2.5-related deaths . 69

The present study has started in April 2020 to highlight the impacts of COVID-19 lockdown on 70 air pollution levels in Morocco and the potentially avoided cause-specific mortality during 71 population quarantine episode. We have adopted the same approach as . To the 72 best of our knowledge, it reports on the first case study that links the COVID-19 to positive 73 . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted July 17, 2020. . https://doi.org/10.1101/2020.07.05.20146589 doi: medRxiv preprint it has killed so far. 75

The remainder of this paper starts with presenting the materials and methods including the study 76 area, the used data and, the adopted approach. It then presents the found results and the discussion 77 section. 78 for air pollution researches as they are the urban areas where serious pollution concerns may be 96 . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted July 17, 2020. 

Air quality, health, and population data 100

The number of daily confirmed COVID-19 cases and death in Morocco were collected from the 101 official website set by the ministry of health for that purpose (Ministry of Health, 2020). Air quality 102 data (daily concentrations of NO2, PM10, and CO) recorded in air quality stations, were gathered 103 from the National Weather Service in charge of air quality management in Morocco. PM10 104 concentrations were then converted to PM2.5 data for each station, using a conversion factor of 0.4 105 (Ait Bouh et al., 2013) . We focused on NO2, PM2·5, and CO because they are traffic-related air 106 . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted July 17, 2020. . https://doi.org/10.1101/2020.07.05.20146589 doi: medRxiv preprint pollutants whose emissions must obviously reduce as a result of the national traffic ban and home 107 quarantine in Morocco during the lockdown. 108 Up to date city-level demographics are obtained from the World Population Review webpage 109 (World Population Review, 2020). Country-level air quality related mortality including that 110 incidental to chronic disease is collected from the Institute for Health Metrics and Evaluation 111 (IHME) (IHME, 2017). 112

To assess air pollution reduction due to the lockdown, we used a difference-in-difference 114 approach that we validated through the non-parametric approach proposed by Theil and Sen for 115 univariate time series (Sen, 1968; Theil, 1950) . Specifically, we defined the before quarantine 116 period as between the 16 th February and the 19 th March 2020 and the during quarantine as between 117 the 20 th March and 20 th April 2020. We assessed changes in air quality during vs. before the 118 quarantine period in 2020 and compared these with corresponding changes in the same lunar 119 calendar periods in 2016-2019. We assessed the statistical significance of the obtained trends using 120 the modified Mann-Kendall test proposed by Hamed and Ramachandra Rao for autocorrelated time 121 series (Hamed and Ramachandra Rao, 1998 ). The test is performed at a significance level of 5%. 122

In order to quantify the impact of the found change in air quality on health, we calculated the 123 avoided cause-specific mortality attributable to the decreases in NO2 and PM2.5 over the study area 124 based on the concentration-response functions from previous studies by (Chen et al., 2018 (Chen et al., , 2017 ) 125 and the cause-specific mortality data from the IHME in 2017 (IHME, 2017). In addition to total 126 non-accidental mortality, the cause-specific mortality for cardiovascular disease, hypertensive 127 disease, stroke, chronic respiratory diseases, and chronic obstructive pulmonary disease (COPD) 128 was also calculated. The attributable fraction (AF) method was used to estimate the daily avoided 129 cause-specific mortality from air pollution reduction as done by . AF is defined 130 . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted July 17, 2020. . https://doi.org/10.1101/2020.07.05.20146589 doi: medRxiv preprint as follows:

= 1 − − ∆ β is the cause-specific coefficient of the CRF, it is expressed as the 131 percentage change in daily mortality associated with a 10 μg/m 3 increase in daily NO2 or PM2.5. β 132 values are available in the study by . Δc is the air quality changes due to the 133 quarantine. AF is then multiplied by the daily cause-specific number of deaths and the total number 134 of days during the quarantine period (32 days) to estimate the cause-specific avoided deaths. 135 is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted July 17, 2020. . https://doi.org/10.1101/2020.07.05.20146589 doi: medRxiv preprint Greenpeace MENA, Morocco is within a lengthy list of countries that suffer relatively from high 163 estimated numbers of deaths annually due to air quality degradation. This number is estimated at 164 5,100 in 2018 (Farrow, A., Miller, K.A. & Myllyvirta, 2020). Dividing this value over 365 days 165 helps obtain the daily average deaths due to air pollution and yields 14 deaths every day. This 166 average fixed value was plotted against the daily reported deaths due to COVID-19 in Morocco 167 (Fig. 4) . Moreover, it is worth noting that outdoor air pollution by particulate matter death rate in 168

Morocco is estimated at 63,1 per 100000 inhabitants (Ritchie, 2019 is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted July 17, 2020. . https://doi.org/10.1101/2020.07.05.20146589 doi: medRxiv preprint air quality that brought health benefits in non-COVID-19 deaths, which could potentially have 186 highly exceeded the current confirmed deaths attributable to COVID-19 in Morocco (229 deaths 187 as of July 3, 2020). 188 The results highlighted in the present work are not isolated and are in agreement with many other 199 studies throughout the world. Thus, this paper and similar ones help to raise awareness about our 200 responsibility towards the environment. It may also help to consider whether the COVID-19 201 lockdown scenario would be an efficient measure for preserving the environment and enhancing 202 life quality in the urban ecosystem. However, cost effectiveness is one of the keys for policymakers 203 to implement any control measure mainly that the lockdown has caused lower mobility and 204 . CC-BY-NC 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted July 17, 2020. . https://doi.org/10.1101/2020.07.05.20146589 doi: medRxiv preprint economic activity and shrinking the economy is not a sustainable solution to encounter the 205 environmental challenge. 206

Moreover, the meteorological forcing is to take into consideration in concluding from such a 207 study as they impact pollutants dispersion and concentration. Overall, the interlinkages between 208 COVID-19, economy and climate are complex and depend on the climatic conditions, the duration 209 of the emergency and reactions to it. Yet, like every crisis, the COVID-19 pandemic offers an 210 important opportunity to draw lessons and to reconsider the way we treat the environment and the 211 ecosystems. 212

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