The impact of COVID-19 pandemic on nitrogen dioxide levels in Nigeria

The Coronavirus disease (COVID-19) has been transmitted worldwide over a very short time after it originated in China in December 2019. In an attempt to control its spread and reduce its health impacts, several countries including those in the African continent imposed restrictive measures that was termed “lockdown”. The outcomes of this lockdown have been reported to be beneficial to air quality worldwide. The main objective of this study is to assess the impact of lockdown due to COVID-19 on nitrogen dioxide (NO2) levels over six major cities in Nigeria. Maps extracted from satellite (Sentinel-5P) were used to indicate the significant reduction in the level of NO2 in the selected cities in Nigeria during two time-intervals, pre-lockdown (December, 2019) and during lockdown (April, 2020). The results show a significant reduction in NO2 levels during the lockdown period compared with its levels during the pre-lockdown period in 2019. The reduction in NO2 concentration levels during lockdown is likely due to less traffic, social distancing and restrictions on business and human activities. There could be an element of uncertainty in the results due to seasonality, as the comparison is done with a different season. However, the magnitude of change due to lockdown is probably much higher than the seasonal variability. Although COVID-19 has negatively impacted the health and economic status of all regions worldwide, it has benefited some aspects of air quality in most countries including Nigeria. This indicates that anthropogenic activities may be managed to reduce air pollution and positively impact the health of human beings

Geographical distribution of the Thuriferous juniper (Juniperus thurifera L.) and the influencing factors in the Atlas Mountains of Azilal (Central High Atlas, Morocco)

ABSTRACTThe present study describes the contribution of geomatic science in mapping and determining the factors influencing the spatial distribution of Juniperus thurifera in the high mountains of Azilal, Morocco. The methodology adopted is based on the use of a Landsat 8 OLI satellite image to determine the spatial distribution of J. thurifera and a WorldClim database to extract the climat conditions.The Digital Elevation Model (DEM) of 30 m resolution was used to derive the topographic parameters. The geological map was digitized and used to derive the different lithological classes. The results obtained show that the J. thurifera tree is distributed in four distinct biogeographic zones (Ait Bouguemez, Zaouit Ahansal, Anergui and Tifirt N'ait Hamza). It is mainly found on the North and/or West-facing aspect at altitudes ranging from 1600 to 3400 m, and on moderate-to-high slopes. It develops with a predominance of limestone, marl-limestone, and sandstone. It prefers areas withclimate types: cold to very cold semi-arid and cold to very cold subhumid. Well-preserved J. thuriferastands can only be observed in certain regions.. These results can be useful in selecting potential sites for reforestation of J.thurifera in similar terrain conditions to develop and manage this species in mountainous areas

Corrigendum to: Sustainable Solid Waste Management in Morocco: Co-Incineration of RDF as an Alternative Fuel in Cement Kilns

The management of municipal solid waste (MSW) is a major obstacle for the majority of municipalities in developing countries because of the impacts related to the landfilling of waste. Garbage is an energy-rich material. As a result, energy recovery is considered to be a sustainable waste management method. In Morocco, 7.4 million tons are produced annually; most of the waste is landfilled without any recovery despite the impacts related to this method of disposal. The objective of this chapter is to characterize combustible fractions (RDF) from household waste in Morocco and to study the economic and environmental benefits of their use as alternative fuels in cement kilns. The results of this research show that the combustible fractions contained in household waste in Morocco constitute a potential sustainable energy source with a high lower calorific value (4454 kcal/kg). The study of the advantages of co-incineration shows that the substitution of pet coke by 15% RDF reduces the pollution linked to gaseous emissions. In addition, the cement plant can make financial savings 389 USD/h by minimizing the use of fossil fuels