The Sub-Saharan Africa (SSA) is the area of Africa’s continent that lies south of the Sahara. The SSA region comprises of 49 African countries that is ecologically, culturally and ethnically separated from Northern Africa by Sahara and Sahel. The SSA covers the southern, western, eastern and central Africa with wide variety of climate zones. Over 1.1 billion people reside in SSA with 40% of the population living below US$ 1.9 daily in 2018 (World Bank, 2020). Most households are left with no other option than to use biomass solid fuels (BSF) for cooking. For decades, cooking with biomass solid fuels had been a great challenge in SSA. The biomass solid fuels (BSF) such as firewood, charcoal, animal dung, agricultural residues, and wastes in households serves as a primary source of energy for cooking and heating in the rural areas with few households in many cities in SSA. The cooking methods of steaming, boiling, frying, roasting, grilling are the common practices among these households (Milanzi & Namancha, 2017; Mchakulu et al., 2019; Ozturk & Bilgili, 2014; Foell et al., 2011; Baumgartner et al., 2019; Joleen & Kozak, 2016; Giwa et al., 2019). However, the exposure to biomass smoke has being in existence since prehistoric ages, man used the solid fuel as primary source of heating in the cold, cooking food and lighting in dark places for thousand of years (Bede-Ojimadu & Orisakwe, 2020). But the practices still dominate SSA countries with evidence from several studies acknowledging the region with the highest percentages of biomass solid fuels use in the world (Ifegbesan et al., 2016; Piddock, et al., 2014; Armah et al., 2019; Lambe et al., 2015; UNEP, 2019; Ravindra et al., 2019).
In a study carried out in 2018, International Energy Agency (IEA 2019) reported that more than 2.6 billion people lack access to clean cooking technologies globally with over 900 million people in the sub-Saharan African (SSA) countries. Access to clean, modern, and affordable energy optimally correlates with human, social, and economic development (Mondal et al., 2018). Moreover, accessibility to clean fuels plays a critical role in attaining sustainable development, mitigation of multidimensional poverty and inequality (Sarkodie & Adams, 2020). The negative impact of the traditional use of biomass solid fuels for cooking on human health and environment across the developing countries remains a topical issue by international development and environmental bodies ( Muller & Yan, 2018; Ifegbesan et al., 2016; Armah et al, 2019; Mensah & Adu, 2015; Jagger et al., 2017). Apparently, the international cooperation to facilitate access to energy efficiency in the region has not been effective as expected since affordable, reliable, and clean energy is still far-fetched for the majority of the populace (Armah et al., 2019).
In spite of an increase in international financial flows to support clean energy in developing countries from $10.1 billion in 2010 to $14 billion in 2018, the impact of the fund is quite insignificant across many Sub-Saharan African countries (IEA, IRENA, UNSD, World Bank & WHO, 2021). Meanwhile, hundreds of million households currently adopt the clean cooking practice in India and China since 2010, as a result of national programs and clean air policies for the adoption of liquefied petroleum gas (LPG) and improved cookstoves (Foell et al., 2011; Baumgartner et al., 2019). Conversely, in sub-Saharan Africa, the analysis from different literature surveys and reports indicate that the transition process still remains acute. The energy progress reported by custodian agencies in 2020 stated a stagnant annual increase rate of 0.4% access to clean fuel due to rapid population growth in SSA. The report indicated that the population growth between 2014 and 2018 surpassed the access to clean fuel growth by an average of 18 million per year (IEA, IRENA, UNSD, World Bank, & WHO, 2020). The uncontrollable expansion coupled with COVID-19 crisis pose a great threat against the actualization of clean cooking among the households.
In 2017, the United Nations Environment Programme (UNEP) established that thirteen countries in SSA including Nigeria, Ethiopia, DR Congo, Tanzania, Kenya, Uganda, and Angola were among the 20 countries with the least access to electricity (UNEP 2019). It was estimated that 4 out of 5 people in these countries rely on biomass solid fuel mainly for cooking. The consumption of the solid fuel varies from country to country depending on the renewable energy policy, electricity accessibility, and availability of forest resources to the populaces (Ozturk and Bilgili, 2014. Biomass solid fuel (BSF) remains the most accessible, affordable energy available for people from substandard economic backgrounds in these regions. The inefficient burning of the BSF in an open fireplace, log burning stoves, or other traditional cooking technologies both indoors and outdoors without any devices or vent arrangements is a common practice for cooking by impoverished households in SSA (Blanke-Roeser, et al., 2016; Felix & Gheewala, 2011; Oguntoke et al., 2010; Keraka et al., 2013; Sadoh et al., 2015; Abd-Elfarag & Langoya, 2016; Tumwesige et al., 2017). The cooking generated emissions from the burning of the biomass solid fuel is a major contributor to household air pollution (HAP) that causes a large number of toxic pollutants associated as one of the leading environmental risks factors for global burden disease (Giwa et al., 2019; Lim et al., 2012; Piddock, et al., 2014; Mocumbi, 2019; Chafe, et al., 2014; Asante, et al., 2016; Shupler et al., 2018 ). The pollutants include heterocyclic compounds, ester, ketones, alkanes, alcohols, carbon monoxide, oxides of nitrogen and sulphur, particulate matter, benzene, formaldehyde, butadiene, polyaromatic compounds, and many other health-damaging chemicals (Felix & Gheewala, 2011; Muller & Yan, 2018; Ravindra et al., 2019; Majdan et al., 2015; Ezzati, 2017; Orifah et al., 2018).
Empirical evidence from related studies show that women and children are most vulnerable to the negative impacts of energy poverty and suffer from the impacts of fuel scarcity, environmental degradation, and HAP (Foell et al., 2011; Mustefa and Lika 2016; IEA, IRENA, UNSD, World Bank, & WHO, 2021; Adusah- Poku & Takeuchi, 2019; Aboubacar et al., 2018). According to 1EA (2019), almost 500,000 deaths were recorded annually relative to household air pollution (HAP) with women and young children severely affected in SSA (Okello et al., 2018; Asante et al., 2016; Karakara et al., 2013; Hafner, 2018; Ifegbesan et al., 2016; ). The report indicates that children under the age of five are more susceptible to increased risk of mortality caused by pollutants emitted from cooking with BSF (Owili et al., 2017). Several epidemiological studies also affirmed the evidence linking the effects of HAP to respiratory diseases, morbidity, mortality, stillbirth, low birth weight, high blood pressure, cataracts, tuberculosis, pneumonia, lung cancer, adverse pregnancy outcomes, and cardiovascular ill-health (Mocumbi, 2019; Ahmed et al., 2015; Ezzati 2017; Alexander, et al., 2018; Das et al., 2016; Mbatchou Ngahane, et al., 2015; Sana et al., 2018; Kurmi et al., 2014).
Arguably, these uncontrollable illegal falling of trees and shrubs in forests and woodlands used as a solid fuel also, result in massive deforestation and desertification as well as soil erosion (Ifegbesan et al., 2016; UNEP, 2019; Megbowon et al., 2018). These environmental hazards are deeply affected mostly among poor populace in the peri-urban and rural areas with high population densities. Obviously, all the aforementioned practices contribute to the increase in greenhouse gas emissions, biodiversity loss, low energy efficiency, and climate change in the vicinity (Takama et al., 2012; Lusambo, 2016; Ifegbesan et al., 2016; Foell et al., 2011;). Currently, the demand for sustainable clean energy is increasing rapidly in SSA as a result of population growth and quest for industrialization. As it stands, the slow progress in clean cooking create a major concern in the realization of Sustainable Developmental goals (SDGs) by stakeholders and international bodies. The United Nations projected that by 2050 a tremendous population of more than 1.8 billion in SSA will still rely on BSF for cooking with more likelihood of the rural dwellers due to low per capita economic growth (UNEP, 2019). This rapid expansion will have a negative influence on access to cleaner cooking fuels and modern technologies among households. The prevalence of BSF use calls for immediate scale-up and acceleration of clean cooking solutions. Outrightly, the quick implementation of efficient technologies and market policy models for the integration of modern fuel by policymakers will immensely bridge the gap of energy deprivation among SSA households (IEA, IRENA, UNSD, World Bank, WHO, 2021).
The findings of relevant studies across the different countries in sub-Saharan Africa lack evidence on the assessment of biomass solid fuel use for traditional cooking in households. Thus the accurate estimation of BSF utilization that utmostly contributes to household air pollution is not clearly understood in most SSA countries. The aim of this review is for comprehensive compilation of articles that investigates the biomass solid fuel (BSF) utilize for traditional cooking in kitchens or outdoor area and analyze its health, socioeconomic and environmental impacts among households in SSA. This paper highlight the various types of BSF adapted for cooking excluding exposure due to occupational air pollution. There is no previous study that complements the existing literature on assessment of biomass utilization in SSA. Our study focuses on exploring the clear evidence that will enhance appropriate interventions by governments or organizations to ensure better cooking technologies practices in households. Implementation of the recommendation from the different works of literature will heighten sustainable development, energy access, energy security, prosperity as well as low carbon emission into the climate.
1.1. Biomass Utilization for Cooking in SSA
The impact of population pressure on the woodland as a primary source of energy is tremendous as majority of the people in SSA still adopt traditional fuels and technologies (AFDB, 2018; IEA, 2019). Many studies acknowledge that most households still use different BSF for traditional cooking despite an increase in income. The choice of fuels for cooking in households’ are influenced by several factors such as socioeconomic status, education, household size, preference of the households, type of housing, and location. The deterioration and exploitation of the forest resources as BSF for domestic cooking and heating is as a result of rapid population growth. The proportion of the population that uses BSF for cooking across the SSA regions between 2000–2018 are shown in Fig. 1 (IEA, 2019).
Over the past decades, there are several studies focusing on the household solid fuel used and its devastating impacts. Weston et al., (2016) lamented the case of the most densely populated area in the landlocked Malawi. The study reported that more than 95% of the Malawian households use BSF as their primary source of energy. Most of the households’ cooking is done by burning wood and crop residues in open fire and the use of local stoves (mbaulas) for charcoal. Likewise, Mozambique was identified as among one of the poorest countries in the world that utilize BSF for daily activities (Mocumbi et al., 2019). Several studies strongly emphasized that women in these countries play major role in the use of BSF for cooking (Okello et al., 2018). Mustefa and Lika (2016) linked energy use with gender and women’s position in the households. They reported the factors that determine the cooking fuel consumption among female-headed households in Southern Ethiopia. The high exploitation of biomass fuel is critical in SSA and lots of irreversible damages have been done across these countries. The evidence of the consequences of unsustainable consumption of BSF is very alarming due to rapid deforestation (Mchakulu et al., 2019). Nlom and Karimov (2014), Giordano et al. (2018), Hafner (2018), Hooper et al (2018), Karakara (2018) reported the quest for cooking and heating with fuelwood in Cameroon, Cote d’Ivoire, Central African Republic (CAR), Senegal, and Ghana respectively. Other studies that investigated the consumption of the BSF for cooking in some SSA countries are shown in Table 1.
1.2. Traditional Cooking Practices in SSA
Cooking represents 80% of residential energy consumption across the SSA countries (Smeets et al., 2017). Globally, the culture and ethnicity of different localities have a powerful influence on methods of cooking, cooking styles, food materials and ingredients, and choice of cooking fuel among many other factors. Conversely, the cooking practices adopted by the majority of households in SSA are mostly on inefficient traditional cookstoves that emit obnoxious pollutants from both the food materials and the combusted biomass fuels (Giwa et al., 2019).
In rural localities of most SSA countries, many households employ the traditional methods of cooking such as three-stone fires, metal charcoal stoves, metal tripod stoves, homemade mud/clay stoves. The traditional cookstoves consist of a single metal triangle or some stones placed on the floor where the wood burnt directly under a cooking pot as shown in Fig. 3. A study in rural Senegalese revealed that women adopt traditional cooking by arranging three stones or metal tripod stoves on the floor of their huts (Hooper et al., 2018). The three-stone fire requires only three stones of relatively equal height on which BSF (burning wood and dried dung cakes) are burnt and the cooking positioned over a fire as shown in Fig. 3a (Kabir et al., 2018). The traditional stoves are designed to adapt to specific cooking styles and fuel types (Rhodes, et al., 2014). A higher proportion of rural households solely depend on these inefficient cookstoves for domestic cooking. Similarly, most households in Madagascar also use wood-burning cookstoves for cooking (Zahana, 2020). These traditional practices of cooking are often characterized by perceptions and cultural beliefs. For instance, the Kenyan households use a small, portable coal-burning stove, known as the jiko and homemade, chepkube for warming and cooking their meals (Rhodes et al., 2014). Dominant use of the traditional stove is attributed to ancestral belief that it cooks properly and yields the right aroma or flavors. These cultural beliefs strongly determine the behaviors of many of the populace on the cooking habits and food tastes (Dickinson et al., 2019; Rhodes et al., 2014). The notion that cooking on traditional stoves improves the taste of dishes is rampant across SSA countries. Most Nigerians prefer the flavor of suya meat grilled over charcoal and the savoring, unique taste of party jollof rice cooked traditionally. They believe that biomass smoke from traditional cookstoves adds more aroma and flavor to the meal. Sati and Maikano (2020) reported that in the rural Northern Nigeria, the villagers prefer a traditional cookstove to any clean cookstove as a result of their strong beliefs that it adds to the food taste and that the smoke from the fire serves as insect repellant in homes. Ochieng et. al (2020) found in Kenya that the quest for tasty meals among most rural households contributes to the attachment to traditional cookstoves.
Beside food taste, the dominant use of the traditional stoves in SSA countries is based on the minimal initial cost, no or less maintenance required and the cooking fuel is oftentimes gathered in the forest at no monetary cost (Dickinson, et al., 2019).