scholarly journals Physico-chemical characterization of urban aerosols from specific combustion sources in West Africa at Abidjan in Côte d'Ivoire and Cotonou in Benin in the frame of the DACCIWA program

2020 ◽  
Vol 20 (9) ◽  
pp. 5327-5354 ◽  
Author(s):  
Aka Jacques Adon ◽  
Catherine Liousse ◽  
Elhadji Thierno Doumbia ◽  
Armelle Baeza-Squiban ◽  
Hélène Cachier ◽  
...  
Keyword(s):  
Organic Carbon ◽  
West Africa ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Dry Season ◽  
Water Soluble ◽  
Wet Season ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Combustion Sources

Abstract. Urban air pollution in West Africa has yet to be well characterized. In the frame of DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) program, intensive measurement campaigns were performed in Abidjan (Côte d'Ivoire) and Cotonou (Benin), in dry (January 2016 and 2017) and wet (July 2015 and 2016) seasons, at different sites chosen to be representative of African urban combustion sources, i.e., domestic fires (ADF), traffic (AT) and waste burning (AWB) sources in Abidjan and traffic source in Cotonou (CT). Both the size distribution of particulate matter (PM) and their chemical composition including elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC), water-soluble inorganic ions (WSI) and trace metals were examined. Results show very high PM concentrations at all sites and a well-marked seasonality as well as a strong spatial variation. The average PM2.5 mass concentrations during the wet season are 517.3, 104.1, 90.3, and 69.1 µg m−3 at the ADF, CT, AT, and AWB sites, respectively. In the dry season, PM2.5 concentrations decrease to 375.7 µg m−3 at the ADF site, while they increase to 269.7, 141.3, and 175.3 µg m−3 at the CT, AT, and AWB sites, respectively. The annual PM2.5 levels at almost all sites are significantly higher than the WHO guideline level of 10 µg m−3. As for PM mass, (EC) and (OC) concentrations are also maximal at the ADF site, accounting for up to 69 % of the total PM mass. Such a high content is mainly linked to wood burning for domestic cooking and commercial food smoking activities. Dust contributions are dominant at CT (57 %–80 %), AT (20 %–70 %), and AWB (30 %–69 %) sites and especially in the coarse and fine-particle modes at the CT site and in the coarse fraction at the AT site, which may be explained by the impact of long-range desert-dust transport and resuspended particles from the roads, in addition to anthropogenic sources. The contributions of WSI to the total PM mass, mainly driven by chloride, nitrate, and calcium in the fine and/or large particles, are highly variable according to the sites but remain less than 30 %. Values are generally 1–3 times higher in the wet season than in the dry season. This is due not only to anthropogenic emissions but also to nitrate formation by reaction processes and natural emissions. The concentrations of trace elements reflect well the trends in dust at the traffic and AWB sites, with a predominance of Al, Na, Ca, Fe, and K, keys markers of crustal dust. This study constitutes an original database that characterizes specific African combustion sources.

scholarly journals Physico-chemical characterization of urban aerosols from specific combustion sources in West Africaat Abidjan in Côte d’Ivoire and Cotonou in Benin in the frame of DACCIWA program

2019 ◽  
Author(s):  
Aka Jacques Adon ◽  
Catherine Liousse ◽  
Elhadji Thierno Doumbia ◽  
Armelle Baeza-Squiban ◽  
Hélène Cachier ◽  
...  
Keyword(s):  
Air Pollution ◽  
West Africa ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Dry Season ◽  
Carbonaceous Aerosol ◽  
Wet Season ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Combustion Sources

Abstract. Air pollution in West Africa is far to be well characterized. It was the rationale of the Air Pollution and Health work package in the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) program. Intensive measurement campaigns were running in two West African capitals (Abidjan in Côte d’Ivoire and Cotonou in Benin), to examine size distribution of the particulate matter (PM) concentrations and their chemical composition (Elemental Carbon (EC), Organic Carbon (OC), Water-soluble organic carbon (WSOC), Water-soluble inorganic ions (WSI) and trace metals). This work aims to characterize PM from different sites in Abidjan, the economic capital of Cote d’Ivoire, typical of Domestic Fire (ADF), Traffic (AT) and Waste Burning (AWB) and Cotonou, the capital of Benin, representative of Traffic (CT). These selected sites, impacted by a large amount of pollution levels, are representative of the main combustion sources prevailing in South West Africa during dry and wet seasons. To address this concern, intensive campaigns in Abidjan and Cotonou have been conducted in July (2015 and 2016) and January (2016 and 2017). Results show a well-marked seasonality, inter-annual and spatial variabilities and the PM levels at the studied areas are generally higher than the WHO guidelines. The average mass concentrations in the wet season were 90.3, 104.1, 69.1 and 517.3 μg m−3 at AT, CT, AWB and ADF sites, respectively. The largest value at ADF site is due to the contribution of smoking and roasting activities. By contrast in the dry season, the concentrations increase to 141.3, 269.7 and 175.3 μg m−3 at AT, CT and AWB site, respectively whereas at ADF site concentration decreases to 375.7 μg m−3. The chemical aerosol mass closure shows that dust contributed for 25–65 % at the both traffic and AWB sites, and 10–30 % at ADF with a clear seasonal cycle. A large variability of POM is observed with contribution range of 37–68 % at ADF, 20–42 % at AT, 10–34 % at AWB and 15–22 % at CT. The contribution of WSI to bulk PM (lower than 20 %) is 2–3 times larger in wet season than dry season, except at ADF site where no season variation is observed. The most dominant species in WSI fraction at ADF are chloride (18–36 % of the total ions), potassium (8–22 %) and calcium (13–25 %), while at the rest of the sites, nitrates (21–36 %), chlorides (6–30 %) and sulfates (9–20 %) are higher. At all sites, the proportion of EC is twice higher in dry season than in wet season. Carbonaceous aerosol (sum of EC and POM) and dust particles are the two major contributors to the different particle fractions with carbonaceous aerosol predominant at Abidjan and dust at Cotonou. The highest carbonaceous aerosol contribution is obtained at ADF (up to 75 % of total PM), while at the other sites its contribution ranges between 18 and 35 %. WSOC levels are higher at the traffic sites during the dry season, while during the wet season they are maximum at ADF and AWB sites. Element trace characterization is also determined, showing predominance of Al, Na and Ca followed by Fe, K and Mg. Our study highlights the contribution of different traffic emissions in two major West African cities in atmospheric aerosol composition but also the one of domestic fire and waste combustion sources. It constitutes an original database to characterize urban air pollution for specific African combustion sources.

scholarly journals Mass concentration, optical depth and carbon composition of particulate matter in the major southern West African cities of Cotonou (Benin) and Abidjan (Côte d'Ivoire)

2018 ◽  
Vol 18 (9) ◽  
pp. 6275-6291 ◽  
Author(s):  
Julien Djossou ◽  
Jean-François Léon ◽  
Aristide Barthélemy Akpo ◽  
Cathy Liousse ◽  
Véronique Yoboué ◽  
...  
Keyword(s):  
Optical Depth ◽  
Cote D'ivoire ◽  
Mass Concentration ◽  
Côte D’Ivoire ◽  
Surface Wind ◽  
Dry Season ◽  
The Other ◽  
Wet Season ◽  
Cote D’Ivoire ◽  
Côte D'ivoire

Abstract. Air quality degradation is a major issue in the large conurbations on the shore of the Gulf of Guinea. We present for the first time PM2.5 time series collected in Cotonou, Benin, and Abidjan, Côte d'Ivoire, from February 2015 to March 2017. Measurements were performed in the vicinity of major combustion aerosol sources: Cotonou/traffic (CT), Abidjan/traffic (AT), Abidjan/landfill (AL) and Abidjan/domestic fires (ADF). We report the weekly PM2.5 mass and carbonaceous content as elemental (EC) and organic (OC) carbon concentrations. We also measure the aerosol optical depth (AOD) and the Ångström exponent in both cities. The average PM2.5 mass concentrations were 32 ± 32, 32 ± 24 and 28 ± 19 µg m−3 at traffic sites CT and AT and landfill site AL, respectively. The domestic fire site shows a concentration of 145 ± 69 µg m−3 due to the contribution of smoking and roasting activities. The highest OC and EC concentrations were also measured at ADF at 71 ± 29 and 15 ± 9 µg m−3, respectively, while the other sites present OC concentration between 8 and 12 µg m−3 and EC concentrations between 2 and 7 µg m−3. The OC ∕ EC ratio is 4.3 at CT and 2.0 at AT. This difference highlights the influence of two-wheel vehicles using gasoline in Cotonou compared to that of four-wheel vehicles using diesel fuel in Abidjan. AOD was rather similar in both cities, with a mean value of 0.58 in Cotonou and of 0.68 in Abidjan. The seasonal cycle is dominated by the large increase in surface mass concentration and AOD during the long dry season (December–February) as expected due to mineral dust advection and biomass burning activities. The lowest concentrations are observed during the short dry season (August–September) due to an increase in surface wind speed leading to a better ventilation. On the other hand, the high PM2.5 ∕ AOD ratio in the short wet season (October–November) indicates the stagnation of local pollution.

scholarly journals Exploration targets in the Côte d'Ivoire-Ghana transform margin in Equatorial West Africa

2010 ◽  
Vol 37 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Liu Jianping ◽  
Pan Xiaohua ◽  
Ma Jun ◽  
Tian Zuoji ◽  
Wan Lunkun
Keyword(s):  
West Africa ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Transform Margin

scholarly journals Tinea Capitis Caused by Microsporum audouninii: A Report of Two Cases from Côte D’Ivoire, West Africa

2021 ◽  
Vol 6 (1) ◽  
pp. 9
Author(s):  
Rie Roselyne Yotsu ◽  
Kouamé Kouadio ◽  
Aubin Yao ◽  
Bamba Vagamon ◽  
Motoi Takenaka ◽  
...  
Keyword(s):  
West Africa ◽  
Dna Sequencing ◽  
Cote D'ivoire ◽  
Tinea Capitis ◽  
Sampling Method ◽  
Côte D’Ivoire ◽  
Adhesive Tape ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Epidemiological Surveys

We report here two cases of tinea capitis caused by Microsporum (M.) audouinii in Côte d’Ivoire, West Africa. The patients were a three-year-old boy and a six-year-old girl who presented with scaly patches on the scalp. The causative fungus was isolated using an adhesive tape-sampling method and cultured on Sabouraud dextrose agar plates. It was identified as M. audouinii both by its macroscopic and microscopic features, confirmed by DNA sequencing. These are the first documented cases of M. audouinii infections confirmed with DNA sequencing to be reported from Côte d’Ivoire. The practicality of the tape-sampling method makes it possible to carry out epidemiological surveys evaluating the distribution of these dermatophytic infections in remote, resource-limited settings.

scholarly journals Premières données sur les variations saisonnières de la communauté d’oiseaux du barrage urbain de Koko (Korhogo, Côte d’Ivoire)

2019 ◽  
Vol 41.2 ◽  
pp. 6926-6939
Author(s):  
NIAMIEN Coffi Jean Magloire ◽  
KONAN Ekoun Michaël ◽  
ODOUKPE Kadio Saint Guillaume ◽  
YAOKOKORE-BEIBRO Kouassi Hilaire ◽  
N’GORAN Kouakou Eliézer
Keyword(s):  
Cote D'ivoire ◽  
Rainy Season ◽  
Côte D’Ivoire ◽  
Well Being ◽  
Dry Season ◽  
Resident Species ◽  
Cote D’Ivoire ◽  
South Central ◽  
Frequent Species ◽  
Côte D'ivoire

Les oiseaux rendent d’importants services écologiques nécessaires au bien-être de l’homme. En Côte d’Ivoire, l’essentiel des études ornithologiques se sont déroulées au sud, et accessoirement au centre et au centre-ouest. En outre, très peu de travaux ont porté sur les zones humides. La ville de Korhogo abrite des barrages à vocation agro-pastorale qui n’ont été l’objet d’aucune étude. Pour combler ce manque de connaissance, une étude a été menée de février 2016 à janvier 2017. L’objectif de ce travail est d’évaluer la richesse spécifique et de déterminer l’influence des saisons sur la distribution qualitative de la communauté des oiseaux du barrage urbain de Koko dans la commune de Korhogo. Pour ce faire, des observations directes, utilisant la méthode des transects ponctuée d’arrêts d’environ 15 minutes, ont été effectuées. Les résultats indiquent que cette communauté est constituée de 63 espèces d’oiseaux appartenant à 32 familles et regroupées en 14 ordres. Globalement, l’ordre des Passériformes et la famille des Ardeidae sont les mieux représentés. Du point de vue de leur statut biogéographique, les espèces résidentes (37 individus : 59 %) et accidentelles (23 individus : 36,51%) sont majoritaires. Le plus grand nombre d’espèces a été observé en saison des pluies (52 individus : 82,54%). Sept espèces ont été spécifiques de la saison sèche alors que trois espèces sont caractéristiques de la saison des pluies. Les espèces résidentes ont été les nombreuses en toute saison. Au niveau structural, les espèces accessoires, les espèces assez-fréquentes et les espèces fréquentes ont été les mieux représentées en saison sèche tandis que les espèces assez-fréquentes ont été majoritaires en saison des pluies. Cette étude confirme la distribution des communautés des oiseaux selon les saisons. ABSTRACT Birds provide important ecosystem services necessary for human well-being. In Côte d'Ivoire, ornithological studies were carried out in the south, central and central-west. In addition, very little work has been done on wetlands. The Commune of Korhogo is home to agro-pastoral dams that have not been studied. To fill in this gap of information, a study was conducted from February 2016 to January 2017. The aim of this study was to assess the specific richness and to examine the effect of seasons on the qualitative distribution of the Koko urban dam birds’ community. Direct observations using the method of line transects with a 15 minutes points were carried out. Results show that this community consists of 63 species of birds belonging to 32 families and grouped in 14 orders. Globally, the order of the Passeriformes and the family of Ardeidae were the best represented. In terms of their biogeographical status, resident species (37 individuals: 59%) and accidental species (23 individuals: 36.51%) were dominant. The high number of bird species was observed during the rainy season (52 individuals: 82.54%). Seven species were specific to the dry season while three species are characteristic of the rainy season. Resident species were numerous in all seasons. The accessory and relatively frequent species have been the most abundant during the dry season while the fairly frequent species were predominant in the rainy season. This study confirms the distribution of bird communities according to the seasons.

scholarly journals Marching across and beyond West Africa: First record of the stem-galling fly Cecidochares connexa (Diptera: Tephritidae) in Central Africa and the implications for biological control of Chromolaena odorata (Asteraceae)

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252770
Author(s):  
Pascal O. Aigbedion-Atalor ◽  
Itohan Idemudia ◽  
Medetissi Adom ◽  
Ethelyn E. Forchibe ◽  
Hospice Tossou ◽  
...  
Keyword(s):  
Biological Control ◽  
West Africa ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Biological Control Agent ◽  
Central Africa ◽  
Chromolaena Odorata ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Benin Republic

The Neotropical invasive plant Chromolaena odorata R.M. King and H. Robinson (Asteraceae) is a serious weed in West and Central Africa and two biological control agents that have been introduced into West Africa to help reduce its impacts on agriculture and biodiversity, have established. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), has spread widely across West Africa since its release in only Côte d’Ivoire, occurring in six countries. This study aimed to investigate whether the gall fly had spread further across West Africa and into Central Africa. Here, we surveyed C. odorata for C. connexa galls in Cameroon between October 2018 and October 2020, along roadsides, on farms, residential areas, and abandoned plots, encompassing various vegetation types. Additional surveys were conducted across four countries (Ghana, Togo, Benin Republic and Nigeria) in West Africa that we considered the probable pathway for the spread of the gall fly into Central Africa. Cecidochares connexa was present at five of the six locations surveyed in Cameroon, albeit in varying abundance. In Africa, these findings represent the first-ever report of C. connexa outside of West Africa. In West Africa, we recorded significant expansion in the geographic range of C. connexa, as reflected in the absent-present record of C. connexa in two locations in Nigeria and one in Ghana, as well as its occurrence in all locations surveyed in Benin Republic and Togo. Clearly, Ghana, Togo, Benin Republic and Nigeria served as the dispersal pathway of C. connexa from the release sites in Côte d’Ivoire into Cameroon, covering over 2,300 km. Following the spread and establishment of C. connexa into Cameroon, we anticipate that it will continue to spread further into other parts of Central Africa which are climatically suitable. Cecidochares connexa is currently the only biological control agent for C. odorata in Central Africa. Given that it has significantly reduced populations of C. odorata in other countries where it has established, it is expected to have a similar impact in Central Africa.

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