Iba Dieudonné Dely

According to the Intergovernmental Panel on Climate Change (IPCC), changes in land cover could increase air temperature in urbanized areas by up to 4 °C by 2100. Urban heat islands are a major concern because of their effects on human health and economic activities. In Côte d’Ivoire, Abidjan is experiencing increasing frequency and intensity of heatwaves. However, the influence of spatiotemporal land use and land cover dynamics on UHI remains poorly documented. This study analyzes land use and land cover dynamics and their influence on UHI in Abidjan between 2002, 2014, and 2024. Landsat and MODIS AQUA data were used to map land cover and land surface temperature. The NDVI and NDBI indices were used to assess the influence of vegetation and built-up areas on UHIs. Relationships were analyzed using Pearson correlation and geographically weighted regression (GWR). Results show a 19.60 % increase in built-up areas and an 18.57 % decrease in vegetated areas. Mean UHI-related temperature increased from 30.22 °C to 31.88 °C, representing a rise of 1.66 °C. NDBI showed positive correlations with UHIs (0.65 in 2002, 0.74 in 2014, and 0.75 in 2024), while NDVI showed negative correlations (-0.63, -0.62, and -0.49, respectively). GWR results indicate spatial variations in these relationships, with predominantly positive NDBI coefficients and negative NDVI coefficients. These findings highlight the association between urbanization, vegetation loss, and UHI intensification in Abidjan, emphasizing the need to preserve vegetation and control urban expansion.

Climate change is accompanied by a growing intensification of temperatures at the local scale, as observed in several cities of the sub-region, yet their evolution and trends remain insufficiently quantified. This study aims to examine the trends and anomalies of temperatures in the city of Abidjan over the period 1985-2024. Daily maximum (TX), minimum (TN), and mean (TM) temperature data, provided by SODEXAM, were analyzed using the Mann-Kendall trend test combined with Sen's slope, as well as an anomaly index calculated relative to the 1985-2024 climatological normal. The results reveal a significant upward trend for both TN and TM over the entire period, with a marked intensification of nocturnal warming (R² = 0.4096). Anomaly analysis shows that 2001, 2002, and 2003 were the coolest years recorded (down to -3.30 °C), while 2008 and 2010 were the warmest (+1.3 °C) over the entire study period. At the monthly scale, February to April consistently concentrate the highest temperatures throughout the study period. Overall, the results reveal an upward thermal trend over the past two decades (since 2005), associated with an increase in minimum and mean temperatures in Abidjan. These results provide a climatological baseline for future research on the specific role of nocturnal warming in aggravating health risk in West African coastal urban settings.

Access to water, sanitation, and hygiene (WASH) is a fundamental determinant of public health in urban African settings. In Côte d'Ivoire, despite recorded progress, significant disparities persist between neighborhoods, particularly in the city of Abidjan. This study aims to document WASH access conditions among populations in two contrasting neighborhoods of Abidjan, namely Williamsville III (a precarious neighborhood) and Palmeraie (an affluent residential neighborhood). A cross-sectional survey was conducted among 403 households (197 in Palmeraie; 206 in Williamsville III) in April 2025. Data were entered in Microsoft Excel and analyzed using descriptive statistical methods in R 4.3.1. Although the water supply source was identical across households, service conditions differed markedly. Water supply interruptions affected 63.6% of households in Williamsville III, compared to only 11.6% in Palmeraie (p < 0.001). Regarding sanitation, septic tanks were the main wastewater disposal method in Palmeraie (80.7%) compared to 55.3% in Williamsville III, where street discharge was more prevalent (11.7% vs 3.6%, p < 0.001). Finally, daily waste collection was more widespread in Palmeraie (46.7% vs 25.7%, p < 0.001). These inequalities call for priority interventions targeting water service continuity and the improvement of sanitation infrastructure in precarious neighborhoods of Abidjan.

Extreme heat events are increasing in frequency and intensity due to climate change, particularly in West Africa. Pregnant women and their fetuses are among the most vulnerable to heat exposure, yet evidence from African settings remains limited. In Abidjan, Côte d’Ivoire, both the frequency and intensity of heat episodes have increased in recent years. However, the effects of maternal heat exposure on adverse pregnancy outcomes have not yet been investigated in this context. This study assessed the relationship between heat exposure and maternal-fetal health outcomes. This retrospective ecological time-series analysis used hospital records from 2014 to 2024 from two maternity hospitals in Yopougon district. Pearson correlation analysis was used to examine associations between mean maximum temperature and preterm birth and miscarriage. A total of 36,376 deliveries were recorded at Wassakara maternity hospital, including 0.69% miscarriage and 0.90% preterm births. At Toit Rouge maternity, 22,294 deliveries were recorded, including 1.71% miscarriages and 1.18% preterm births. Annual and seasonal trends showed fluctuations in both outcomes. Pearson correlation analyses indicated broadly similar associations in both maternity hospitals, with weak positive associations between mean maximum temperature and the pregnancy outcomes studied, and a weak negative association for preterm birth in Wassakara maternity hospital. However, none of these associations were statistically significant. These findings suggest a potential association between heat exposure and adverse perinatal outcomes, including preterm birth and miscarriage, highlighting the need for further research considering more data and sources and targeted preventive strategies for pregnant women.

African cities are increasingly vulnerable to the effects of climate change, and to air pollution in particular. However, the comparison of measured data with people's perceptions remains an open question. This study aimed to characterize the seasonal variability of fine (PM2.5) and coarse (PM10) particulate matter, both outdoors and inside dwellings, in Yopougon (Abidjan), and to compare it with residents' perceptions. Continuous instrumental monitoring was carried out over 195 days (August 2024 to March 2025) in two neighborhoods of Yopougon, designated zone A and zone B respectively, using PurpleAir Flex sensors deployed indoors and outdoors to obtain real-time PM2.5 and PM10 measurements. The hourly data were subsequently aggregated into daily averages. In parallel, a perception survey was conducted among 525 respondents. The results show that the measured PM2.5 and PM10 concentrations were well above the WHO guideline values, although PM10 exceeded them only during the dry season. PM2.5 pollution was more pronounced indoors than outdoors, with a median concentration higher by 6.14 µg/m³ in zone A and 2.24 µg/m³ in zone B. The measurements indicate that the pollution peak occurred in December; however, residents perceived February and March as the most polluted months. This reveals a one-month lag between the population's perception of the pollution peak and the actual measurements. These findings advocate for public policies promoting anticipated awareness campaigns, from the onset of the dry season, based on measurement rather than on perception alone.

Extreme heat events are associated with increased morbidity and mortality, disproportionately affecting vulnerable populations. However, evidence from disadvantaged urban settings in Africa remains scarce. This systematic review aimed to synthesize existing research on the health impacts of extreme heat in Africa’s disadvantaged urban communities. A systematic literature search was conducted in accordance with PRISMA guidelines across eleven databases (PubMed, Cochrane, VHL, Google Scholar, ScienceDirect, Research4Life, DOAJ, Emerald, Taylor & Francis, Annual Reviews, and IRIS), carried out over two search periods (December 2023–March 2024 and December 2024–February 2025). Eligible studies were published between 2010 and 2024 in English, French, or Portuguese, and examined direct or indirect heat-health effects in disadvantaged urban settings. Screening of 96,608 titles and 59 abstracts yielded 21 eligible studies. Geographically, the evidence was concentrated in South Africa (n = 7), Kenya (n = 6), and Tanzania (n = 4), with single studies from Cameroon, Egypt, Nigeria, and Ghana. Heat-related morbidity was examined in 17 studies and mortality in four. Commonly reported conditions included dehydration, heat exhaustion, skin rashes, heatstroke, and cardiovascular and respiratory diseases. Extreme heat was further associated with mortality from non-communicable diseases, pneumonia, and acute respiratory infections. Children, older adults, and the most economically deprived communities exhibited heightened vulnerability, driven by adverse socioeconomic and environmental conditions. The available evidence confirms substantial heat-health impacts on disadvantaged urban populations across Africa, while revealing a notable research gap in French- and Portuguese-language literature. These findings underscore the urgent need for expanded, geographically and linguistically diverse research to inform climate adaptation strategies and health protection policies.

Malaria is the leading cause of morbidity among children under five years of age and pregnant women in Côte d’Ivoire. We assessed the geographical distribution of its risk in all climatic zones of the country based on the Fifth Assessment Report (AR5) of the United Nations Intergovernmental Panel on Climate Change (IPCC) approach to climate risk analysis. This methodology considers three main driving components affecting the risk: Hazard, exposure and vulnerability. Considering the malaria impact chain, various variables were identified for each of the risk factors and for each variable, a measurable indicator was identified. These indicators were then standardized, weighted through a participatory approach based on expert judgement and finally aggregated to calculate current and future risk. With regard to the four climatic zones in the country: Attieen (sub-equatorial regime) in the South, Baouleen (humid tropical) in the centre, Sudanese or equatorial (tropical transition regime) in the North and the mountainous (humid) in the West. Malaria risk among pregnant women and children under 5 was found to be higher in the mountainous and the Baouleen climate, with the hazard highest in the mountainous climate and Exposure very high in the Attieen climate. The most vulnerable districts were those in Baouleen, Attieen and the mountainous climates. By 2050, the IPCC representative concentration pathway (RCP) 4.5 and 8.5 scenarios predict an increase in risk in almost all climatic zones, compared to current levels, with the former considering a moderate scenario, with an emissions peak around 2040 followed by a decline and RCP 8.5 giving the highest baseline emissions scenario, in which emissions continue to rise. It is expected that the AR5 approach to climate risk analysis will be increasingly used in climate risk assessment studies so that it can be better assessed at a variety of scales.