The realization of the scale, magnitude, and complexity of the water and sanitation problem at the global level has compelled international agencies and national governments to increase their resolve to face the challenge. There is extensive evidence on the independent effects of urbanicity (rural-urban environment) and wealth status on access to water and sanitation services in sub-Saharan Africa. However, our understanding of the joint effect of urbanicity and wealth on access to water and sanitation services across spatio-temporal scales is nascent. In this study, a pooled regression analysis of the compositional and contextual factors that systematically vary with access to water and sanitation services over a 25-year time period in fifteen countries across sub-Saharan Africa (SSA) was carried out. On the whole, substantial improvements have been made in providing access to improved water sources in SSA from 1990 to 2015 unlike access to sanitation facilities over the same period. Households were 28.2 percent and 125.2 percent more likely to have access to improved water sources in 2000–2005 and 2010–2015 respectively, than in 1990–1995. Urban rich households were 329 percent more likely to have access to improved water sources compared with the urban poor. Although access to improved sanitation facilities increased from 69 percent in 1990–1995 and 74 percent in 2000–2005 it declined significantly to 53 percent in 2010–2015. Urban rich households were 227 percent more likely to have access to improved sanitation facilities compared with urban poor households. These results were mediated and attenuated by biosocial, socio-cultural and contextual factors and underscore the fact that the challenge of access to water and sanitation in sub-Saharan Africa is not merely scientific and technical but interwoven with environment, culture, economics and human behaviour necessitating the need for interdisciplinary research and policy interventions.

COVID-19 is an active pandemic that likely poses an existential threat to humanity. Frequent handwashing, social distancing, and partial or total lockdowns are among the suite of measures prescribed by the World Health Organization (WHO) and being implemented across the world to contain the pandemic. However, existing inequalities in access to certain basic necessities of life (water, sanitation facility, and food storage) create layered vulnerabilities to COVID-19 and can render the preventive measures ineffective or simply counterproductive. We hypothesized that individuals in households without any of the named basic necessities of life are more likely to violate the preventive (especially lockdown) measures and thereby increase the risk of infection or aid the spread of COVID-19. Based on nationally-representative data for 25 sub-Saharan African (SSA) countries, multivariate statistical and geospatial analyses were used to investigate whether, and to what extent, household family structure is associated with in-house access to basic needs which, in turn, could reflect on a higher risk of COVID-19 infection. The results indicate that approximately 46% of the sampled households in these countries (except South Africa) did not have in-house access to any of the three basic needs and about 8% had access to all the three basic needs. Five countries had less than 2% of their households with in-house access to all three basic needs. Ten countries had over 50% of their households with no in-house access to all the three basic needs. There is a social gradient in in-house access between the rich and the poor, urban and rural richest, male- and female-headed households, among others. We conclude that SSA governments would need to infuse innovative gender- and age-sensitive support services (such as water supply, portable sanitation) to augment the preventive measures prescribed by the WHO. Short-, medium- and long-term interventions within and across countries should necessarily address the upstream, midstream and downstream determinants of in-house access and the full spectrum of layers of inequalities including individual, interpersonal, institutional, and population levels.

Access to clean cooking fuels is critical for human health and features, prominently in the UN Sustainable Development Goals. However, our understanding of the probabilities of access to clean cooking across sub-Saharan Africa (SSA) is emergent. A pooled regression analysis of the compositional and contextual factors that cumulatively influence access to clean cooking fuels in 31 SSA countries, between 2010 and 2016, was carried out. Household access to clean cooking fuels across the 31 countries was just 10%. Access of urban households to clean cooking fuels was 26% and it was 2% for rural households. Higher probabilities of access were observed for households that were rich and highly educated compared with households that were either rich but with low education or poor but highly educated. Middle households with heads educated to secondary level or higher in both urban and rural areas almost have the same chance with the rich households with uneducated heads or educated to primary level regarding access to clean cooking fuels. The average probability of poor households with heads educated to secondary level or higher is twice that of poor households with uneducated heads or educated to primary level. The average probability of access to clean cooking of rich households with heads educated to secondary or higher level is ten times higher than for poor households with uneducated heads. These findings are mediated and attenuated by compositional and contextual factors, giving credence to the fact that the challenge of access to clean cooking fuels in SSA is multifaceted and requires interdisciplinary research and policy interventions encompassing health, environment, culture, and economics.

Many children under five years still die from diarrhoeal diseases globally even though much progress has been made. The threat to public health posed by diarrhoeal diseases warrants the need to understand the interaction of the disease determinants from a spatio-temporal perspective to inform policy and intervention design. In this study, a pooled regression analysis was carried out using the Ghana Demographic and Health Survey data on 15,808 children under five years, to assess the combined effect of environmental factors on childhood diarrhoea prevalence and morbidity over a 21-year period. Childhood diarrhoea prevalence declined steadily from 20% to 16% from 1993 to 2003 but increased to 20% in 2008 and finally decreased significantly to 12% in 2014. The strength of the association between diarrhoea prevalence and each of the predictors presented in decreasing order of magnitude were as follows: current age of child, geographical region, religion, mother's highest educational level, ethnicity, source of drinking water and toilet facility, residential wellbeing, birth order, age of mother, and sex of child. Regional and temporal heterogeneities in prevalence, rate and distribution of diarrhoea were observed, indicating the need for context-specific interventions and policies.

Constructed wetlands have been proposed to address the frequency and magnitude of oil and gas-related environmental contamination. The effect of co-variation of hydraulic load and hydraulic retention time on the dynamics of contaminant removal efficiency of heterogeneous plant species was assessed using ordinary least squares regression. The results showed that hydraulic load (HL), hydraulic retention time (HRT) and plant species jointly explain 87%, 79%, 83%, 85% and 66% of the total variance in removal efficiency of conductivity, TDS, BOD, COD, and total coliform bacteria, respectively. The models also explain 86%, 80% and 81% of the variations in removal efficiency of oil and grease, total phosphorus, and nitrate. More than 90% of the explained variance of total coliform removal efficiency is jointly attributable to hydraulic load and retention time. Hydraulic load of 1000 L and retention time of 72 h (1000 L 72 h) recorded optimum removal efficiency for TDS and conductivity. Optimum removal efficiency for BOD, COD and total coliform bacteria were achieved at HL and HRT of 1000 L 72 h, 1000 L 48 h and 1250 L 24 h, respectively. Alternanthera philoxeroides recorded the highest removal efficiency for oil and grease, conductivity and TDS, whereas Ruellia simplex recorded the highest removal efficiency for COD. Typha latifolia had the highest removal efficiency for total phosphorus and nitrate. Plant species suppressed the relationship between HL and HRT (1250 L 48 h, 1500 L 72 h, 1750 L 48 h and 2000 and removal efficiency for conductivity. Similarly, plant species suppressed the relationship between 1000 L 48 h and 1750 48 h and removal efficiency for TDS. These relationships underscore the complex dynamics between optimal contaminant removal efficiency and required hydraulic load, hydraulic retention time and plant species.