Assessing the PM

and O

Concentrations Changes during and after

Easing the Lockdown (COVID-19) in the North-western Cities of

Morocco: An Overview

Nezha Mejjad

, Salah-Eddine Sbai

, El-Khalil Cherif

, Ismail Elhassnaoui

Arjun Suresh

, Aniss

Moumen

, Ouafa El-Hammoumi

and Ahmed Fekri

Department of Geology, Faculty of Sciences Ben M'Sik, Hassan II University, Casablanca, Morocco

Department of Physics, Faculty of Sciences Rabat, Mohammed V University, Rabat, Morocco

Institute for Systems and Robotics, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal

Hydraulic System Analysis Team, Mohammadia School of Engineers, Mohammed V University, Rabat, Morocco

Amity Institute of Environmental Science, Amity University, Noida, India

National School of Applied Sciences of Kenitra, University of Ibn Tofail, Kenitra, Morocco

Keywords: Air quality, Ozone, PM

, COVID-19, Lockdown, Morocco.

Abstract: In order to limit the propagation of COVID-19 among the Moroccan population, all industrial activities have

been suspended since March 20th 2020. The present study investigates the possible change in atmospheric

pollutants (ozone O

, particulate matter PM

) rate during the imposed lockdown. We explore air quality

change in Morocco's North-Western cities using the Copernicus Atmosphere Monitoring Service (CAMS)

regional model that provides estimated emissions of pollutants into the atmosphere. The results show an

apparent decrease in PM

levels during the lockdown, which points out the impact of human activities on air

quality. The ozone shows an increasing tendency, which is probably linked to improved photochemical

reactions due to the rise of sunlight passing by the atmosphere, resulting in decreased PM concentrations. This

period that the world is experiencing has drastically impacted socio-economic sectors, but it has proved that

human activities are the main factor influencing the environment.

1 INTRODUCTION

The North-West part of Morocco is known for

concentrating the most important industrial activities,

and it covers the most urbanized cities, including

Casablanca (the economic capital), Tangier, Rabat

(The country's capital), Salé, and Kénitra, among

other cities. However, Casablanca and Tangier house

the central industrial units in the Moroccan Kingdom,

generating different pollutants.

Road transportation also contributes to air

pollution, especially with the urban evolution over the

last decades, which leads to increasing demand for

motor vehicles. According to khatmi et al. (1998),

Casablanca is impacted by year-round air pollution

while, in 2015, the care density reached 104

vehicles/1000 inches (OICA, 2015). Despite the

importance of the transport sector for the country's

economic growth, it is also considered as a polluting

sector of the air and contributes to Morocco's

greenhouse gas emissions by 15% (Inchaouh and

Tahiri, 2017). In recently published work by Mejjad

et al., 2021a, the manufacturing of face masks

generates a greenhouse gas footprint of 224 kT CO

eq./y calculated in Casablanca Settat and Rabat-Salé-

Kénitra regions, while for the whole of Morocco is

around 640 kT CO2 eq./y. Although the increase of

human activities emissions of pollutant into the air

caused over Morocco in 2014, 2,200 deaths, while

about 50% of adults' deaths were from Casablanca,

Marrakech, and Tangier (Croitoru and Sarraf, 2017).

As human activities are the primary source

contributing to air quality deterioration (Sbai et al.,

2020; Manisalidis et al., 2020; Christidou and

Dimitriou, 2011), the suspension of these activities

during the COVID-19 pandemic is the best occasion

to assess the air quality change and evaluate the

impact of human activities on the environment. The

rapid spread of COVID-19 around the world has led

the world health organization (WHO) to recommend

specific safety measures to be taken by countries

authorities in the whole world to contain the virus

Mejjad, N., Sbai, S., Cherif, E., Elhassnaoui, I., Suresh, A., Moumen, A., El Hammoumi, O. and Fekri, A.

Assessing the PM10 and O3 Concentrations Changes during and after Easing the Lockdown (COVID-19) in the North-western Cities of Morocco: An Overview.

DOI: 10.5220/0010739300003101

In Proceedings of the 2nd International Conference on Big Data, Modelling and Machine Learning (BML 2021), pages 523-532

ISBN: 978-989-758-559-3

 2022 by SCITEPRESS – Science and Technology Publications, Lda. All rights reser ved

523

propagation and limit the human-to-human contagion

through halting all economic and social activities,

including industrial activities and transportation.

Accordingly, likewise all the world countries, the

Moroccan authority has taken many safety measures

to avoid the increase of daily recorded cases, which

translated by the suspension of all human activities

from March 20

to 11

June 2020, while the whole

country was under imposed lockdown during this

period.

According to HCP, 2020 (in

tradingeconomics.com), there was a decrease in

automotive and metallurgical products by 20.3% and

14.7%, respectively, while the manufactories of

pharmaceutical, chemicals, and paper products

increased by 17.5%, 8.2%, and 9.5%. The Gross

Domestic Product (GDP) transport in Morocco has

also known a significant decline during the COVID-

19 in the first quarterly of 2020 (HCP, 2020). The

effect of coronavirus on the economy is evident in

almost all countries globally and represents the

world's worst economic and social crisis (Ozili, 2020;

Shakeel et al., 2020, Mejjad et al., 2021b).

Conversely, an indirect positive impact of COVID-19

on the environment was reported in many studies

related to coronavirus and the environment, where the

enforced lockdown has indirectly contributed to air

and beaches water quality improvement and

environmental noise decrease (Sbai et al., 2021;

Suresh et al., 2020; Zambrano-Monserrate et al.,

2020; Chauhan and Singh, 2020; Lal et al., 2020;

Dantas et al., 2020; Dutheil et al., 2020; Kerimray et

al., 2020; Kerimray et al., 2020; Li et al., 2020;

Mahato, Pal and Ghosh, 2020; Tobías et al., 2020; He

et al., 2020; Nakada and Urban, 2020; Sharma et al.,

2020). However, few studies have analyzed this

change in Moroccan cities (Salé; Otmani et al., 2020;

Tangier; Cherif et al., 2020).

Thus, the present work sought to assess the

change in air quality before, during and after the

lockdown. Furthermore, the study provides a general

picture of the lockdown impact on the environment

by evaluating the variation of PM

and O

in the

North-Western part of Morocco.

2 METHODS

2.1 Study Area

Morocco is situated in the northern part of Africa. The

northern coastal regions house the most important

industrial activities (Fig.1). Numerous human

activities were concentrated in the Casablanca and

Tangier cities, including industrial and urban

activities (Cherif et al., 2019). The Casablanca-Settat

Region is the highest urbanized region in Morocco

with more than 11 million inhabitants (HCP, 2014),

while the cities of this region (Casablanca;

Mohammedia; El Jadida) have known since the 70s

the growth of human activities through the progress

of different sectors such as industrialization,

agriculture, tourism, land use, and maritime

transportation, among others (Mejjad et al., 2018;

Mejjad et al., 2020a, Mejjad et al., 2020b, Mejjad et

al., 2021c). While the region of Rabat-Salé-Kénitra

also has known the development of human activities

in the last decades and houses many industrial units

in the province of Kénitra (El Khodrani et al., 2020;

El Jalil et al., 2020; Bounakhla et al., 2009). These

regions were the most affected by COVID-19, while

fewer confirmed cases were detected in the Saharan

areas (Daraa-Tafilalt) and in the regions where the

human densities and activities are relatively low.

Figure 1: Location of the study area.

BML 2021 - INTERNATIONAL CONFERENCE ON BIG DATA, MODELLING AND MACHINE LEARNING (BML’21)

524

2.2 Copernicus Atmosphere

Monitoring Service (CAMS) Data

The maps of pollutant indicators used in the present

study were obtained by a Copernicus Atmosphere

Monitoring Service (CAMS) regional model that

provides estimated emissions of pollutants into the

atmosphere during COVID-19 in European countries

downloaded from

(https://atmosphere.copernicus.eu/european-air-

quality-information-support-covid-19-crisis). CAMS

delivers a variety of daily values based on

combinations between information received from

atmospheric numerical models, satellite and ground-

based (in situ) by a process named data assimilation

(European Centre for Medium-Range Weather

Forecasts (ECMWF), CAMS, 2020). The ECMWF

delivers the CAMS global products. As these Maps

cover the North-West and North-East parts of

Morocco, we used this data to evaluate air quality

change during COVID-19.

In the present study, we downloaded maps acquired

before enforced the lockdown in Morocco (March

12th 2020), during the lockdown (March 25th, 13 and

23 April, 13 and 25 May), during the removal of the

lockdown. The easing of the lockdown measures was

applied gradually, in phases, and according to the

cases registered in each prefecture and province, the

kingdom was divided into two zones, A and B (Zone

A: is not under lockdown and Zone B: is under

lockdown). The 1st phase of easing the lockdown for

some provinces and prefectures included Tetouan,

Meknes, Settat, and El Hoceima (June 11th 2020).

The 2nd phase of removing the lockdown has known

the second classification of provinces and prefectures

according to the number of detected cases, which

comprised Casablanca, Fez and more cities (June

25th 2020) (Fig. 2).

Figure 2: Evolution of COVID-19 in Morocco from the start to the removal of lockdown

3 RESULTS AND DISCUSSIONS

Nearly almost all countries worldwide were under

partial or total lockdown because of the COVID-19

spread, which caused the suspension of industrial

activities and road traffic, undoubtedly leading to the

shutdown of pollutants levels in the air. We

investigate the COVID-19 lockdown effect on air

quality by comparing the O

, PM

values recorded

before and during the quarantine.

3.1 Meteorological Conditions

The meteorological conditions, including

temperature, wind speed, precipitation, and relative

humidity, are the key factors influencing atmospheric

pollutants' distribution (Zhou et al., 2018; Zhang et

al., 2015; Li et al., 2011).

The meteorological parameters such as

temperature, wind speed, humidity, and precipitation

recorded during 13 and 25 March; 13 and 23 April;

13, May 25th; and 11, 25 and 30 June are presented

in Fig.3. Substantial temperature variation in the

Northwest, Northeast, East and West of Morocco

Assessing the PM10 and O3 Concentrations Changes during and after Easing the Lockdown (COVID-19) in the North-western Cities of

Morocco: An Overview

525

characterizes the period from March to June (Fig. 3).

The humidity was relatively high during the periods

extending from March to early May and decreased

progressively from late May. The humidity rate is

higher in coastal cities (Tangier, Rabat, and

Casablanca) than in continental cities like Er-

rachidia. The average temperatures show a similar

trend and increase progressively during the lockdown

in the months known as a transition season (March-

April) (Rodríguez et al., 2001) and reached 40°C in

late May in continental cities (Fez and Er-rachidia).

Figure 3: Meteorological conditions during 13 and 25 March; 13 and 23 April; 13, May 25th; and 11, 25 and 30 June (Source:

www.wunderground.com).

3.2 Spatial Mass Concentrations

Changes of O

and PM

before,

during, and after the Lockdown

Period

3.2.1 Spatial Pattern of Ozone (O3) Mass

Concentration.

Figure 4 shows the spatial evolution of the Ozone

mass concentration over North-Western cities of

Morocco for March 12th (before lockdown); 13

April 23rd and 13

, May 25th (During lockdown);

June 11th (1

phase easing the lockdown) and 25

, June (2

phase easing the lockdown). A crucial

increase in ozone levels was observed during the

lockdown (March 17

). This increase in O

could be

attributed to the drastic drop in ozone titration by

and NO (Mahato et al., 2020; Siciliano et al.,

2020; Freitas et al., 2020) and some other pollutants

related directly to human activities and road traffic,

such as volatile organic component (VOC), SO2, CO

(Han and Naeher, 2006). On March 13th (before

lockdown), the O

mass concentration varied between

75 and 105 µg/m

; the values were less critical in

Tangier, Tetouan, Fez, Méknes, Rabat and

Casablanca and high in the western region. The

concentrations were increased during the lockdown

and reach values up to 120 µg/m

on May 25th, higher

than daily permissible values recommended by WHO

and Moroccan limit values (100 µg/m

; 110 µg/m

)

respectively (Chirmata et al., 2018; WHO, 2006).

Moreover, the values were higher in western cities

characterized by low human and car density, which

means low NOx levels. As the photochemical

reactions are a significant source of an oxidizing

factor in the atmosphere, such as ozone (Hu et al.,

2019), the increase of ozone can also be explained by

the improvement of photochemical reactions due to

the rise of sunlight passing by the atmosphere

resulting in decreased PM concentrations (Li et al.,

2019; Dang and Liao, 2019). On the other hand, the

BML 2021 - INTERNATIONAL CONFERENCE ON BIG DATA, MODELLING AND MACHINE LEARNING (BML’21)

526

augmentation of solar radiation during the lockdown

(especially during April-March-June) shows that the

growth of O3 is usual during this period of the year

due to higher solar radiation, especially under high

humidity. Krug et al. (2019) have reported that the

seasonal effects may often have impacts on ozone

production (being high during hot days). Recently,

some research showed that the growth in daylight

hours might be a crucial factor causing higher O

levels (Collivignarelli et al., 2020).

During the first stage of easing the lockdown (June

), the ozone values show a slight decrease in the

whole study area and reach 100 µg/m3except for some

cities classified as zone (A), the O

values reach 80

µg/m

. The ozone has declined in the following days

that have known the second phase of lockdown easing

(from June 25

), which included this time Casablanca-

Settat, Rabat- Salé- Kénitra, Fez- Méknes, and

Tangier- El Hoceima-Tetouan regions while the

values were ranged from 70 to 100 µg/m

Figure 4: Map of O

daily max concentration, (Credit: ECMWF, Copernicus Atmosphere Monitoring Service (CAMS))

3.2.2 Spatial Pattern of PM

Mass

Concentration

The particle matter (PM) is an essential indicator of

air quality strongly related to primary sources like

road traffic, coal combustion, biomass burning, dust

mineral, and chemical fuel emissions (Zhang et al.

2018). The secondary sources are related to volatile

organic compounds (VOC) and

biogenic VOC

conversion to particle via atmospheric oxidation

involving O3 and O.H. oxidation (Ortega et al., 2016;

Liu et al., 2018; palm et al., 2016 and 2017; Sbai and

Farida, 2019; Yalçin et al., 2020). Sea salt, like

iodine, can be a product of ultra-fine particles after

oxidation, especially under high O

levels (Saiz-

Lopez and Plane 2004; Gómez Martín et al., 2013;

Sbai and Bentayeb, 2019). NO

and SO

can produce

ammonium particles and sulfate particles after

atmospheric oxidation (Wang et al., 2019; Khoder,

2002). The spatial distributions of diurnal PM

mass

concentrations are presented in Fig.5. A substantial

change was observed during the lockdown compared

to before and during the lockdown.

The PM

levels were ranged between 20 and

25µg/m

in Casablanca, Rabat, and Tangier some

days before enforcing the lockdown, below the limit

values recommended by WHO (WHO, 2006). PM

dropped in the North-West area of Morocco during

Assessing the PM10 and O3 Concentrations Changes during and after Easing the Lockdown (COVID-19) in the North-western Cities of

Morocco: An Overview

527

the lockdown and reached 10µg/m

on April 13

. In

the North-East, the PM

mass concentrations were

very high (~ 50µg/m

) compared to the North-West

cities, attributed to the dust mineral particles, because

the Saharan dust is a substantial primary source of PM

(Kabatas et al., 2012). The PM

values were higher

during March and April (during lockdown),

especially in the West, which can be explained by the

transport of dust particles from the Sahara in the

northeast, which is in good accordance with studies

that reported that the Saharan-dust proliferation

occurs during the transition seasons (March-April),

(Rodríguez et al., 2001; Gerasopoulos et al., 2006;

Kallos et al., 2007; Mitsakou et al., 2008; Querol et

al., 2009; Kabatas et al., 2012). Moreover, we show a

reduction of PM

after lockdown (June 11

) in the

northeast, and this can be explained by the decrease

in wind speed (Fig.4) and dust particles transport.

Besides, we have recorded a substantial decrease in

PM level in all regions of the study area during the

lockdown; this is due to the decrease of the main

primary sources of PM, such as road traffic and

industrial activities, especially in the industrial pole

of the country (Casablanca and Tangier) (Kumar et

al., 2020). In addition, the precipitations were more

frequent during the lockdown period. This variation

of meteorological conditions was adequate for

reducing atmospheric pollutants concentrations

during the lockdown, especially for the coastal cities

but unfavourable for continental cities.

Despite the easing of imposed lockdown on June

, the PM

values are below 10µg/m

Casablanca, Rabat, Tamera, Tangier, and Fez (Fig.5).

These cities were ranked as zone B, which does not

follow criteria established by the health authority and

then they were excluded from the ease of lockdown

measures. The values have increased during the

second stage of removing the lockdown, and reach

values ranged from ~10 to ~20 µg/m

on June 25

and

from ~20 to ~40 µg/m

on June 30

. The restarting of

human activities, including industrial activities and

road traffic, is the origin of PM increases. Otherwise,

the PM

values do not exceed WHO's guidelines for

air quality and the Moroccan air quality standards

(Chirmata et al., 2018; WHO, 2006). The observed

changes in PM

values reflect the influence of human

activities on the environment and the positive effect

of the imposed lockdown caused by COVID-19, in

good agreement with recent studies related to the

impact of COVID-19 on air quality (Chen et al., 2020;

Tobías et al., 2020; He et al., 2020; Otmani et al.,

2020).

Figure 5: Spatial PM

daily mass concentration change in the North-Western cities of Morocco (Credit: ECMWF,

Copernicus Atmosphere Monitoring Service (CAMS)).

BML 2021 - INTERNATIONAL CONFERENCE ON BIG DATA, MODELLING AND MACHINE LEARNING (BML’21)

528

4 CONCLUSIONS

The present study gives an overview of air quality

changes before, during, and after imposing the

lockdown in North-East and North-West parts of

Morocco and highlights the human activities effects

on air quality. Generally, an apparent change in PM

and O3 levels are shown in CAMS's daily maps. An

apparent reduction of PM

levels was observed

during the imposed lockdown while the ozone levels

have increased during the same period. The

increasing trend of ozone concentrations is most

likely related to the improvement of photochemical

reactions due to the rise of sunlight passing by the

atmosphere due to reducing PM levels.

The change in atmospheric pollutants levels is

linked to the temporary suspension of human

activities that contribute to air quality degradation,

such as road traffic and industrial activities.

The air quality was monitored in every country

globally, which revealed that humans are the main

factor influencing environmental quality. All the

studies focused on environmental assessment and

monitoring have associated increased pollutant levels

on air, soil, and water with human activities. Putting

almost all human activities on pause as a response to

COVID-19 has improved environmental quality and

proved the human effect on the planet's environment.

Future research needs to be elaborated to

investigate the air pollution levels change in

Morocco, especially in cities known for high

pollutant emissions, to explore whether air quality

improvement has positively affected human health.

RECOMMENDATIONS

Indeed, the social and economic sectors were

dramatically affected by the imposed lockdown and

the suspension of all economic activities, including

international trade, but the environment has taken

advantage of these safety measures. The COVID-19

experience is an open invitation to stakeholders,

decision-makers, society, and environmentalist actors

to reconsider the impact of humans on the

environment and elaborate new and more efficient

policies and strategies to fight against environmental

quality deterioration.

ACKNOWLEDGEMENTS

The authors of this work would like to thank the

CAMS and ECMWF for approving the use of maps

data presented in this work.

REFERENCES

Adams M.D. 2020. Air pollution in Ontario, Canada during

the COVID-19 State of Emergency. Sci. Total Environ.

742:140516. doi:10.1016/j.scitotenv.2020.140516.

Baldasano J.M. 2020. COVID-19 lockdown effects on air

quality by NO 2 in the cities of Barcelona and Madrid

(Spain). Sci. Total Environ. 741, 140353.

https://doi.org/10.1016/j.scitotenv.2020.140353.

Bao R., Zhang A. 2020. Does lockdown reduce air

pollution? Evidence from 44 cities in northern China.

Sci Total Environ 731: 139052.

https://doi.org/10.1016/j.scitotenv.2020.139052

Bounakhla M., Zghaid M., Zahry F., Tahri M., Benyaich F.,

Noack Y., Benkirane O., Saidi N. 2009. Assessment of

air pollution in the city of Kenitra Evaluation de la

pollution atmosphérique de la ville de Kénitra. Phys.

Chem. News 45, 22-29.

Carlsen L., Bruggemann R., Kenessov B. 2020. Use of

partial order in environmental pollution studies

demonstrated by urban BTEX air pollution in 20 major

cities worldwide. Sci. Total Environ., 610–611 (2018),

pp. 234 243, 10.1016/j.scitotenv.2017.08.029

Chauhan A., Singh RP. 2020. Decline in PM2.5

concentrations over major cities around the world

associated with COVID-19. Environ Res 187: 109634.

https://doi.org/10.1016/j.envres.2020.109634.

Chen R.J., Yin P, Meng X., Liu C., Wang L.J., Xu X.H.,

Ross J.A., Tse L.A., Zhao Z.H., Kan H.D., Zhou M.G.

2017. Fine Particulate Air Pollution and Daily

Mortality A Nationwide Analysis in 272 Chinese Cities

Am. J. Resp. Crit. Care, 196 (2017), pp. 73-81.

Cherif K., Vodopivec M., Mejjad N., Silva E., Simonovič

S., Boulaassal H. 2020. COVID-19 impact on coastal

water quality using WST Sentinel-3 data: Case of

Tangier, Morocco. Water (ISSN 2073-4441) Water

2020, 12, 2638; doi:10.3390/w12092638.

Chirmata A., Leghrib R., and Ichou I.A. 2017.

Implementation of the Air Quality Monitoring Network

at Agadir City in Morocco. Journal of Environmental

Protection, 8, 540-567.

https://doi.org/10.4236/jep.2017.84037.

Collivignarelli M.C., Abbà A., Bertanza G., Pedrazzani R.,

Ricciardi P., Miino M.C. 2020. Lockdown for CoViD-

2019 in Milan: What are the effects on air quality?,

Science of The Total Environment, Volume 732, 2020,

139280, ISSN 0048-9697,

https://doi.org/10.1016/j.scitotenv.2020.139280.

Croitoru L., and Sarraf M. 2017. Estimating the Health Cost

of Air Pollution: The Case of Morocco. Journal of

Environmental Protection, 8, 13 p.

Assessing the PM10 and O3 Concentrations Changes during and after Easing the Lockdown (COVID-19) in the North-western Cities of

Morocco: An Overview

529

Dang R., Liao H. 2019. Radiative forcing and health impact

of aerosols and ozone in China as the consequence of

clean air actions over 2012–2017. Geophys. Res. Lett.

2019;46:12511–12519.

Dantas G., Siciliano B., França B.B., Da Silva C.M., Arbilla

G. 2020. The impact of COVID-19 partial lockdown on

the air quality of the city of Rio de Janeiro, Brazil. Sci.

Total Environ. 729, 139085.

Dimitriou A., Christidou V. 2011. Causes and

Consequences of Air Pollution and Environmental

Injustice as Critical Issues for Science and

Environmental Education, The Impact of Air Pollution

on Health, Economy, Environment and Agricultural

Sources, Mohamed K. Khallaf, IntechOpen, DOI:

10.5772/17654. Available from:

https://www.intechopen.com/books/the-impact-of-air-

pollution-on-health-economy-environment-and-

agricultural-sources/causes-and-consequences-of-air-

pollution-and-environmental-injustice-as-critical-

issues-for-science-

Dutheil F., Baker JS., Navel V. 2020. COVID-19 as a factor

influencing air pollution? Environ Pollut.263: 114466.

https://doi.org/10.1016/j.envpol.2020.114466

El Jalil M.H., Elkrauni H., Khamar M., Bouyahya A,

Elhamri H., Cherkaoui E., and Nounah A. 2020.

Physicochemical characterization of leachates

produced in the Rabat-Salé-Kénitra Region landfill

technical center and monitoring of their treatment by

aeration and reverse osmosis. E3S Web Conf., 150

(2020) 02013DOI:

https://doi.org/10.1051/e3sconf/202015002013

El Khodrani N., Omrania S., Nouayti A., Zouahri A.,

Douaik A., Iaaich H., Lahmar M., And Fekhaoui M.

2020. Comparative Study of Groundwater Pollution of

M'nasra and Sfafaa zones (Gharb, Morocco) by

Nitrates. E3S Web of Conferences 150, 0100 (2020)

https://doi.org/10.1051/e3sconf/20201500100.

Freitas E.D., Ibarra-Espinosa S.A., Gavidia-Calderón M.E.,

Rehbein A., Abou Rafee S.A., Martins J.A., Martins

L.D., Santos U.P., Ning M.F., Andrade M.F., Trindade

R.I.F. 2020. Mobility Restrictions and Air Quality

under COVID-19 Pandemic in São Paulo, Brazil.

Preprints, 2020040515 (doi:

10.20944/preprints202004.0515.v1).

Gerasopoulos E., Kouvarakis G., Babasakalis P.,

Vrekoussis M., Putaud J.P., Mihalopoulos N. 2020.

Origin and variability of particulate matter (PM10)

mass concentrations over the Eastern Mediterranean

Atmos. Environ., 40 (2006), pp. 4679-4690.

Gómez Martín J.C., Gálvez O., Baeza-Romero M.T.,

Ingham T., Plane J.M.C., Blitz M.A. 2013. On the

mechanism of iodine oxide particle formation.Phys.

Chem. Chem. Phys. 15, 15612.

https://doi.org/10.1039/c3cp51217g.

Han X., Naeher L.P. 2006. A review of traffic-related air

pollution exposure assessment studies in the developing

world. Environment International 32 (2006) 106 – 120.

doi:10.1016/j.envint.2005.05.020

HCP 2020. Morocco GDP 1960-2020 data available in

tradingeconomics.com (Acessed in May 6th 2020)

He L., Zhang S., Hu J, Li Z., Zheng X., Cao Y., Xu G., Yan

M., Wu Y. 2020. On-road emission measurements of

reactive nitrogen compounds from heavy-duty diesel

trucks in China. Environ. Pollut, 2020, 114280.

Hu Z., Wessels H.J.C.T, Van Alen T., et al. 2019. Nitric

oxide-dependent anaerobic ammonium oxidation. Nat

Commun 10, 1244. https://doi.org/10.1038/s41467-019

09268-w

Inchaouh M., and Tahiri, M. 2017. Air pollution due to road

transportation in Morocco: evolution and impacts.

Journal of Multidisciplinary Engineering Science and

Technology (JMEST) ISSN: 2458-9403 Vol. 4 Issue

Kabatas B., Pierce R.B., Unal A., Rogal M.J., Lenzen A.

2008. Saharan dust event: Its contribution to PM10

concentrations over the Anatolian Peninsula and

relation with synoptic conditions, Science of The Total

Environment, Volume 633, 2018, Pages 317-328, ISSN

0048-9697,

https://doi.org/10.1016/j.scitotenv.2018.03.150.

Kallos G., Astitha M., Katsafados P., Spyrou C. 2007.

Long-range transport of anthropogenically and

naturally produced particulate matter in the

Mediterranean and North Atlantic: current state of

knowledge. J. Appl. Meteorol. Climatol., 46 (2007), pp.

1230-1251.

Kerimray A., Baimatova N., Ibragimova O.P., Bukenov B.,

Kenessov B., Plotitsyn P., Karaca F. 2020. Assessing

air quality changes in large cities during COVID-19

lockdowns: The impacts of traffic-free urban conditions

in Almaty, Kazakhstan. Sci. Total Environ. 139179.

Khatami A., Ponche J.-L., Jabry E., Mirabel Ph, 1996.

Répartition spatiale des émissions atmosphériques dans

le Grand Casablanca (1992). Publ. de l’AIC, 9, pages

349-357.

Khoder MI; 2002. Atmospheric conversion of sulfur

dioxide to particulate sulfate and nitrogen dioxide to

particulate nitrate and gaseous nitric acid in an urban

area. Chemosphere. 2002 Nov;49(6):675-684. DOI:

10.1016/s0045-6535(02)00391-0.

Kumar P., Hama S., Omidvarborna H., Sharma A., Sahani

J., Abhijith K.V., Debele S.E., Zavala-Reyes J.C.,

Barwise Y., Tiwari A. 2020. Temporary reduction in

fine particulate matter due to 'anthropogenic emissions

switch-off' during COVID-19 lockdown in Indian

cities, Sustainable Cities and Society, Volume 62, 2020,

102382, ISSN 2210-6707,

https://doi.org/10.1016/j.scs.2020.102382.

Krug A., Fenner D., Holtmann A., Scherer D. 2019.

Occurrence and Coupling of Heat and Ozone Events

and Their Relation to Mortality Rates in Berlin,

Germany, between 2000 and 2014. Atmosphere 10,

348. https://doi.org/10.3390/atmos10060348.

Li L., Li Q., Huang L., Wang Q., Zhu A., Xu J., Liu Z., Li

H., Shi L., Li R. 2020. Air quality changes during the

COVID-19 lockdown over the Yangtze River Delta

Region: An insight into the impact of human activity

pattern changes on air pollution variation. Sci. Total

Environ. 2020, 139282.

BML 2021 - INTERNATIONAL CONFERENCE ON BIG DATA, MODELLING AND MACHINE LEARNING (BML’21)

530

Li K., Jacob D.J., Liao H., Shen L., Zhang Q., Bates K.H.

2019. Anthropogenic drivers of 2013–2017 trends in

summer surface ozone in China. Proc. Natl. Acad. Sci.;

116:422–427.

Li L., Chen C.H., Fu J.S., Huang C., Streets D.G., Huang

H.Y., Zhang G.F., Wang Y.J., Jang C.J., Wang H.L, et

al. 2020. Air quality and emissions in the Yangtze River

Delta, China. Atmos. Chem. Phys. 2011, 11, 1621–

1639.

Lian X., Huang J., Huang R., Liu C., Wang L., Zhang T.

2020. Impact of city lockdown on the air quality of

COVID-19-hit of Wuhan city [published online ahead

of print, 2020 June 30th]. Sci Total Environ.

2020;742:140556.

doi:10.1016/j.scitotenv.2020.140556.

Liu J., Chu B., Chen T., Liu C., Wang L., Bao X., He H.

2018. Secondary Organic Aerosol Formation from

Ambient Air at an Urban Site in Beijing: effects of O.H.

Exposure and Precursor Concentrations. Environ. Sci.

Technol. 52, 6834 6841.doi:10.1021/acs.est.7b05701.

Lu X., Zhang L., & Shen L. 2019. Meteorology and Climate

Influences on Tropospheric Ozone: a Review of Natural

Sources, Chemistry, and Transport Patterns. Curr

Pollution Rep 5, 238–260 (2019).

https://doi.org/10.1007/s40726-019-00118-3

Mahato S., Pal S., Ghosh K.G. 2020. Effect of lockdown

amid COVID-19 pandemic on air quality of the

megacity Delhi, India. Sci. Total Environ. 2020,

139086.

Manisalidis I., Stavropoulou E., Stavropoulos A.,

Bezirtzoglou E. 2020. Environmental and Health

Impacts of Air Pollution: A Review. Front Public

Health. 2020;8:14. doi:10.3389/fpubh.2020.00014

Mejjad N., Laissaoui A., El-Hammoumi O., Fekri A., Amsil

H., El-Yahyaoui A., Benkdad A. 2018. Geochemical,

radiometric, and environmental approaches for the

assessment of the intensity and chronology of metal

contamination in the sediment cores from Oualidia

lagoon (Morocco). Environ SciPollutRes

(https://doi.org/10.1007/s11356-018-2370-y.

Mejjad N., Laissaoui A., Fekri A., Benmhammed A., El

Hammoumi O., Cherif E. 2020a. Does human activities

growth lead to biodiversity loss in the Moroccan coastal

lagoons? A diagnostic comparison study. In

Proceedings of ACM GEOIT4W-2020, March 11–12,

2020, Al-Hoceima, Morocco, 5 pages.

https://doi.org/10.1145/3399205.3399231.

Mejjad N., Laissaoui A., El-Hammoumi O., Hassen N. H.,

Fekri A., Benkdad A., Amsil H. 2020b. Tracking

natural and human impact on sediment dynamics using

radiometric approach in Oualidia lagoon (Morocco),

International Journal of Environmental Analytical

Chemistry. DOI: 10.1080/03067319.2020.1782394.

Mejjad N., Cherif E.K., Rodero A., Krawczyk D.A., El

Kharraz J., Moumen A., Laqbaqbi M., Fekri A.

Disposal Behavior of Used Masks during the COVID-

19 Pandemic in the Moroccan Community: Potential

Environmental Impact. Int. J. Environ. Res. Public

Health 2021a, 18, 4382.

https://doi.org/10.3390/ijerph18084382.

Mejjad, N., Yaagoubi, H., Moumen, A., Md. Refat Jahan

Rakib. 2021b. The role of social media in delivering

news related to the COVID-19 pandemic: Moroccan

community as a case study. SHS Web Conf., 119 (2021)

07007. DOI:

https://doi.org/10.1051/shsconf/202111907007.

Mejjad N., Rossi A., Elkhalidi Kh., Pavel A-B., Cherif El

Kh., and El Ouaty. 2021c. A SWOT Analysis to

understand the impact of the tourism industry on the

Three pillars social Economy and Environment. SHS

Web Conf., 119 (2021) 04004. DOI:

https://doi.org/10.1051/shsconf/202111904004.

Mitsakou C., Kallos G., Papantoniou N., Spyrou C.,

Solomos S., Astitha M., Housiadas C. 2008. Saharan

dust levels in Greece and received inhalation doses.

Atmos. Chem. Phys., 8 (2008), pp. 7181-7192

Nakada L.Y.K., Urban, R.C. 2020. COVID-19 pandemic:

Impacts on the air quality during the partial lockdown

in São Paulo state, Brazil. Sci. Total Environ.2020,

2020, 139087.

Organisation Internationale des Constructeurs

d’Automobiles” (OICA). 2015. Available at

:http://www.oica.net/category/vehicles-in-use/

(Accessed 09 May 2020).

Ortega A.M., Hayes PL., Peng Z., Palm BB., Hu W., Day

DA., Li R., Cubison MJ., Brune WH., Graus M et al.

2016. Real-time measurements of secondary organic

aerosol formation and aging from ambient air inan

oxidation flow reactor in the Los Angeles area.

AtmosChemPhys 16:7411–7433.

https://doi:10.5194/acp-16-7411-2016.

Otmani A., Benchrif A., Tahri M., Bounakhla M., Chakir

E.M., El Bouch M., Krombi M. 2020. Impact of Covid-

19 lockdown on PM10, SO2 and NO2 concentrations in

Salé City (Morocco). Sci. Total Environ. 735, 139541.

https://doi.org/10.1016/j.scitotenv.2020.139541

Ozili P.K. 2020. COVID-19 in Africa: socio-economic

impact, policy response and opportunities. International

Journal of Sociology and Social Policy, Vol. ahead-of-

print No. ahead-of-print.

https://doi.org/10.1108/IJSSP-05-2020-0171.

Pal B.B., Campuzano-Jost P., Ortega A.M., Day D.A.,

Kaser L., Jud W, et al. 2016. In situ secondary organic

aerosol formation from ambient pine forest air using an

oxidation flow reactor. Atmos. Chem. Phys. 16, 2943–

2970.doi:10.5194/acp-16-2943-2016.

Palm B.B., Campuzano-Jost P., Douglas A. D., Ortega

A.M., Day D.A., Kaser L., Jud W, et al. 2017.

Secondary organic aerosol formation from in situ O.H.,

O3, and NO3 oxidation of ambient forest air in an

oxidation flow reactor. Atmos. Chem. Phys., 17, 5331–

5354, 2017.

Rodríguez S., Querol X., Alastuey A., Kallos G.,

Kakaliagou O. 2001. Saharan dust contributions to

PM10 and TSP levels in Southern and Eastern Spain.

Atmos. Environ., 35 (2001), pp. 2433-2447.

Saiz-Lopez A., Plane J. 2004. Novel iodine chemistry in the

marine boundary layer. Geophys. Res. Lett., 2004, 31,

L04112. https://doi.org/10.1029/2003GL019215.

Assessing the PM10 and O3 Concentrations Changes during and after Easing the Lockdown (COVID-19) in the North-western Cities of

Morocco: An Overview

531

Sbai S.E., Farida B. 2019a. Photochemical aging and

secondary organic aerosols generated from limonene in

an oxidation flow reactor. Environ. Sci. Pollut. Res. 26,

18411–18420. https://doi.org/10.1007/s11356-019-

05012-5.

Sbai S.E., Farida B. 2019b. Study of Iodine Oxide Particles

at the Air/Sea Interface in the Presence of Surfactants

and Humic Acid. Chem. Chem. Technol. 13, 341–346.

https://doi.org/10.23939/chcht13.03.341.

Sbai S.E, Mejjad N., Norelyaqine A., Bentayeb F. 2021. Air

quality change during the COVID-19 pandemic

lockdown over the Auvergne-Rhône-Alpes region,

France. Air Quality, Atmosphere & Health.

https://DOI: 10.1007/s11869-020-00965-w.

Shakeel S ., Ahmed Hassali MA., Abbas Naqvi A. 2020.

Health and economic impact of COVID-19: mapping

the consequences of a pandemic in Malaysia. Malays J

Med Sci. 2020;27(2):159–164.

https://doi.org/10.21315/mjms2020.27.2.16

Sharma S., Zhang M., Gao J., Zhang H., Kota SH. 2020.

Effect of restricted emissions during COVID-19 on air

quality in India. Sci Total Environ. 728:138878. doi:

10.1016/j.scitotenv.2020.138878.

Siciliano B., Dantas G., da Silva C.M., Arbilla G. 2020.

Increased ozone levels during the COVID-19

lockdown: Analysis for the city of Rio de Janeiro,

Brazil. Sci. Total Environ. 737, 139765.

https://doi.org/10.1016/j.scitotenv.2020.139765.

Singh, R.P., Chauhan, A. 2020. Impact of lockdown on air

quality in India during COVID-19 pandemic. Air Qual

Atmos Health 13, 921–928 (2020).

https://doi.org/10.1007/s11869-020-00863-1.

Srivastava S., Kumar A., Bauddh K., Gautam A.S., Kumar

S. 2020. 21-Day Lockdown in India Dramatically

Reduced Air Pollution Indices in Lucknow and New

Delhi, India. Bulletin of environmental contamination

and toxicology, 105(1), 9–17.

https://doi.org/10.1007/s00128-020-02895-w

Suresh D., Chauhan A., Othmani N., Bhadauria S., Aswin

J., Jose N., Mejjad. N. 2020. Diagnostic Comparison of

Changes in Air Quality over China before and during

the COVID-19 Pandemic. Preprint in Research square).

Doi: 10.21203/rs.3.rs-30482/v1.

Tobías A., Carnerero C., Reche C., Massagué J., Via M.,

Minguillón M.C., Alastuey A., Querol X. 2020.

Changes in air quality during the lockdown in

Barcelona (Spain) one month into the SARS-CoV-2

epidemic. Sci. Total Environ. 726, 138540.

https://doi.org/10.1016/j.scitotenv.2020.138540.

Wang Z., Zhang ., Lv G., Sun X., Wang N., Li Z. 2019.

Synergistic Reaction of SO2 with NO2 in Presence of

H2O and NH3: A Potential Source of Sulfate Aerosol.

Int. J. Mol. Sci. 2019, 20, 3746.

WHO 2006. WHO Air quality guidelines for particulate

matter, ozone, nitrogen dioxide and sulfur dioxide.

Global update 2005. Retrieved July 8th 2020 from

http://whqlibdoc.who.int/hq/2006/WHO_SDE_PHE_

OEH_06.02_eng.pdf.

Yalçin E., Tecer L.. H, Yurdakul S., Tuncele G. 2020.

Potential sources and measured concentrations of

VOCs in Balikesir ambient atmosphere. Atmósfera,

[S.l.], v. 33, n. 3, p. 269-284, june 2020. ISSN 2395-

8812. doi:https://doi.org/10.20937/ATM.52646.

Zambrano-Monserrate M.A., Ruano M.A., Sanchez-

Alcalde L. 2020. Indirect effects of COVID-19 on the

environment. Sci. Total Environ. 728, 138813.

https://doi.org/10.1016/j.scitotenv.2020.138813

Zangari S., Hill DT., Charette AT., Mirowsky JE. 2020. Air

quality changes in New York City during the COVID-

19 pandemic. Sci Total Environ. 742:140496.

doi:10.1016/j.scitotenv.2020.140496.

Zhang L., Wang T., Lv M.Y., Zhang Q. 2015. On the

severe haze in Beijing during January 2013: Unraveling

the effects of meteorological anomalies with WRF-

Chem. Atmos. Environ. 104, 11–21.

Zhang R., Liu C., Zhou G. et al. 2018. Morphology and

property investigation of primary particulate matter

particles from different sources. Nano Res. 11, 3182–

3192 (2018). https://doi.org/10.1007/s12274-017-

1724-y.

Zhang Y. 2019. Dynamic effect analysis of meteorological

conditions on air pollution: A case study from Beijing.

Sci. Total Environ. 684, 178–185.

https://doi.org/10.1016/j.scitotenv.2019.05.360

Zhou S., Peng S., Wang M., Shen A., Liu Z. 2018. The

Characteristics and Contributing Factors of Air

Pollution in Nanjing: A Case Study Based on an

Unmanned Aerial Vehicle Experiment and Multiple

Datasets. Atmosphere 2018, 9, 343;

doi:10.3390/atmos9090343.

BML 2021 - INTERNATIONAL CONFERENCE ON BIG DATA, MODELLING AND MACHINE LEARNING (BML’21)

532