Household air pollution from cooking remains a major public health and climate challenge in low-income urban areas. In Kibera informal settlement in Nairobi, Kenya high population density living in poorly ventilated houses, surrounded with poor waste management and use of charcoal in inefficient stoves and kerosene expose people to harmful emissions. This study assessed household energy use, cooking time, and emissions of carbon monoxide (CO), carbon dioxide (CO2) and fine particulate matter (PM2.5) from cooking with charcoal, kerosene, liquefied petroleum gas (LPG), and electricity under real-world conditions, and explored implications for health and climate policy. Participatory cooking tests of breakfast and dinner were conducted in three households that used all four fuel types identified in a household survey. Real-time measurements of CO, CO2, and PM2.5 were taken before, during, and after cooking. Data were analysed using Welch's ANOVA with Games-Howell post hoc tests. Cooking with any fuel resulted into some household air pollution and charcoal and kerosene produced the highest concentrations of the studied gases and particles. LPG and electricity produced low concentrations and there was no significance difference between the two. The household ambient PM2.5 was 213 mu g/m3 implying that people are living in houses with this pollutant being 14.2 times above the 24-h threshold of 15 mu g/m3 by World Health Organization guidelines. Hence no fuel switch alone will address household air quality in the informal settlement. Transitioning households to clean(er) cooking stackings such as with renewable ecooking, improved charcoal cookstoves and LPG scenario showed the highest reduction of emissions contributing toward Kenya's nationally determined contribution of 32% reduction green house gases emission. Clean(er) cooking stacking aimed at net zero should consider sustainable sourcing of the fuel. There is also need for integration of green spaces for air pollutions removal and reduction of emissions from activities such as burning of waste in open spaces, industrial processes and transport.

In Africa the population of refugees is increasing, resulting in ‘accidental urban centres’ often in remote arid landscapes. Firewood and charcoal, the main sources of cooking energy on the continent, are in short supply in refugee settings. This research is based on a series of interrelated studies conducted among Kalobeyei refugee and host communities in Northwestern Kenya using mixed methods from social and natural sciences. Firewood is inadequate, and 95% of households exchanged or sold food to buy cooking fuel. Energy poverty leaves women feeling disempowered and frustrated and causes conflicts between the refugee and host communities. Charcoal briquettes produced and used by the women emerged as a viable cooking fuel. Women stated that marketing challenges and difficulties in sourcing the raw materials may hinder growth of briquettes as a business. Possible solutions include using biomass from the invasive Prosopis juliflora (currently used for charcoal), establishing “briquette kiosks”, and integrating briquettes into development plans. In refugee contexts, approaches to food insecurity should integrate cooking energy and give women an opportunity to voice their needs and aspirations.

Woodfuel that is unsustainably sourced and inefficiently used results in negative environmental and health impacts. This study assessed charcoal use and resultant concentrations of indoor air pollutants (IAP) in an urban informal settlement while cooking with a Jikokoa stove (an improved branded charcoal stove) and medium and small-sized artisanal Kenya Ceramic Jikos (KCJs). Fuel stacking was prevalent with charcoal and kerosene being used by 25% of the studied households. Cooking with a Jikokoa stove reduced charcoal consumption by 6.4% and 26% compared to small and medium-sized KCJs, respectively. The small-sized KCJ reduced charcoal consumption by 21% compared to the medium-sized KCJ. The Jikokoa stove reduced concentrations of carbon monoxide (CO) by 10% and 50% and fine particulate matter (PM2.5) by 6% and 77% compared to small-sized and medium-sized KCJs, respectively. The Jikokoa stove reduced carbon dioxide (CO2) concentrations by 15.6% compared to the medium-sized KCJ. The small-sized KCJ reduced CO and PM2.5 concentrations by 45% and 75%, respectively, compared to the medium-sized KCJ. In summary, small-sized KCJs are more effective than medium-sized ones, and Jikokoa stoves more effective than small-sized KCJs, making it the stove of choice. The more efficient charcoal stoves are, the more charcoal consumption and IAP can be reduced, mitigating environmental degradation, climate change and health problems associated with smoke in the kitchen. There is need for participatory research to scale improved stoves and upgrade local practices as they are cheaper and already embedded in the cooking culture.

In rural Kenya, firewood is used for cooking and heating by 9 out of every 10 households due to its affordability, availability and convenience. This study was carried out using social and natural science methods to understand women's energy burdens and the reasons for the persistent use of firewood. Firewood remains the main source of energy even when multiple fuels are used ("fuel stacking"). Collecting firewood from forests limits women's earning potential and has a negative impact on their well-being although it is a source of income for some as they sell part of what they gather. In these modern times no one would expect that the prospect of freezing to death due to lack of firewood in the tropical highlands worries aging women, but it does. Women's burden of collecting firewood could be lifted by bringing firewood closer through use of residues from trees on farms and burning it in more efficient cookstoves although there may be gender-specific barriers for some women. Income from sale of two timber trees was adequate to meet the cost of labour for pruning trees on-farm and carrying home a year's supply of firewood for families without members who can do the work. This information is useful towards improving rural women's wellbeing and the sustainability of cooking energy. Knowledge gaps still exist in nature, causes and impacts of energy burdens and solutions that work for the people.

Multiple mycotoxins were tested in milled rice samples (n = 200) from traders at different milling points within the Mwea Irrigation Scheme in Kenya. Traders provided the names of the cultivar, village where paddy was cultivated, sampling locality, miller, and month of paddy harvest between 2018 and 2019. Aflatoxin, citrinin, fumonisin, ochratoxin A, diacetoxyscirpenol, T2, HT2, and sterigmatocystin were analyzed using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS). Deoxynivalenol was tested using enzyme-linked immunosorbent assay (ELISA). Mycotoxins occurred in ranges and frequencies in the following order: sterigmatocystin (0–7 ppb; 74.5%), aflatoxin (0–993 ppb; 55.5%), citrinin (0–9 ppb; 55.5%), ochratoxin A (0–110 ppb; 30%), fumonisin (0–76 ppb; 26%), diacetoxyscirpenol (0–24 ppb; 20.5%), and combined HT2 + T2 (0–62 ppb; 14.5%), and deoxynivalenol was detected in only one sample at 510 ppb. Overall, low amounts of toxins were observed in rice with a low frequency of samples above the regulatory limits for aflatoxin, 13.5%; ochratoxin A, 6%; and HT2 + T2, 0.5%. The maximum co-contamination was for 3.5% samples with six toxins in different combinations. The rice cultivar, paddy environment, time of harvest, and millers influenced the occurrence of different mycotoxins. There is a need to establish integrated approaches for the mitigation of mycotoxin accumulation in the Kenyan rice.

Biochar produced in cookstoves has the potential to contribute to negative carbon emissions through sequestration of biomass carbon while also providing other benefits for sustainable development, including provision of clean renewable energy and increased yields in tropical agriculture. The aim of the reported research was to estimate effects on food production, household energy access and life cycle climate impact from introduction of biochar-producing cookstoves on smallholder farms in Kenya. Participatory research on biochar production and use was undertaken with 150 Kenyan smallholder farming households. Gasifier cookstove functionality, fuel efficiency and emissions were measured, as well as biochar effects on agricultural yields after application to soil. Cookstoves provided benefits through reduced smoke, fuel wood savings and char production, but challenges were found related to labour for fuel preparation, lighting and refilling. On-farm trials with varying rates of biochar inputs, in combination with and without mineral fertilizers, have led to a sustained increase of maize yields following one-time application. The climate impact in a life cycle perspective was considerably lower for the system with cookstove production of biochar and use of biochar in agriculture than for current cooking practices. Climate benefits from biochar production and use are thus possible on smallholder farms in sub-Saharan Africa, through reduced use of biomass in cooking, reduced emissions of products of incomplete combustion and sequestration of stable biochar carbon in soils. Biochar-producing cookstoves can be implemented as a climate change mitigation method in rural sub-Saharan Africa. Successful implementation will require changes in cooking systems including fuel supply, as well as farming systems, which, in turn, requires an understanding of local socio-cultural conditions, including power relations and gender aspects.

Eradicating poverty and achieving food and nutrition security in a sustainable environment is difficult to achieve without adequate access to affordable cooking fuel.It is therefore important to understand the common sources of cooking energy used by people in rural areas and the challenges faced in making fuel sources economically viable, socially acceptable and ecologically sustainable.In the sub-Saharan Africa (SSA) region, more than 90% of the population relies on firewood and charcoal (wood fuel, collectively) as a primary source of domestic energy.Wood fuel sustainability is challenged by unsustainable harvesting and inefficient methods of converting wood into energy.The use of inefficient cook stoves contributes to wood wastage and smoke exposure associated with severe illnesses.Households often abandon traditional nutritious diets that take a long time to cook, reduce the number of meals, and spend income on fuel at the expense of food costs.Innovations exist that have the potential to provide affordable and cleaner tree-based cooking fuel.Pruning trees on the farm as a fuel source brings firewood closer to women, lightens their workload, saves time and reduces income spent on cooking fuel.Using briquettes or gas cook stoves can reduce health risks associated with food preparation and reduce income spent on cooking fuel due to increased fuel efficiency.The development of these innovations indicates the need for a multi-disciplinary approach to increase awareness of the benefits of cooking fuel innovations, encourage further research on product quality enhancement and standardization, to understand cultural and behavioral issues influencing adoption, and integrate innovations into bioenergy policy frameworks.

Degradation of agricultural soils and forest resources are two pervasive challenges in rural landscapes of sub-Saharan Africa. Biochar-producing biomass gasification technologies attract evermore interest because these can empower small-scale farmers to produce energy and food more sustainably byimproving energy use efficiencies, lowering emissions and strengthening climate resilience. In order to assess the potential impacts and the feasibility of soil biochar amendments we are carrying out on-farm trials with 150 households in three agroecosystems in Kenya. A participatory approach was followed for testing uptake of gasifier cook stoves and effects of biochar use on crop production. The outcomes that will be presented include: (a) the degree of feasibility, (b) the effects on crop yields, (c) the general attitudes towards the idea of using the cookstoves to produce biochar, and (d) patterns of biomass fuel use. Effects of domestically produced biochar, at rates of 1-10 t DW ha-1, on the production of maize (Zea mays) and kale (Brassica oleracea) were compared with normal farming practices. At the site located in Kwale the yield increases of maize showed a strong positive correlation with biochar dose. In the first season, yields increased from 0.9 Mg ha-1 in the control plot to 4.4Mg ha-1 in average in the biochar-amended plots. At another site (Siaya), an average biochar dose of 2.8 Mg ha-1 lead to an increase in maize yields from 2.9 to 3.8 Mg ha-1 in average in the first season and from 1.7 to 2.5 Mg ha-1 in the second season after biochar addition. Findings from this action research indicate that producing and using biochar on small-scale farms offers suitable opportunities to close yield gaps across Kenya and in similar agro-ecological environments. (Less)

Biomass fuels dominate the household energy mix in sub-Saharan Africa. Much of it is used inefficiently in poorly ventilated kitchens resulting in indoor air pollution and consumption of large amounts of wood fuel. Micro-gasification cookstoves can improve fuel use efficiency and reduce indoor air pollution while producing char as a by-product. This study monitored real-time concentrations of carbon monoxide (CO), carbon dioxide (CO2) and fine particulate matter (PM2.5), and amount of firewood used when households were cooking dinner. Twenty-five households used the gasifier cookstove to cook and five repeated the same test with three-stone open fire on a different date. With the gasifier, the average corresponding dinner time CO, CO2, and PM2.5 concentrations were reduced by 57%, 41%, and 79% respectively compared to three-stone open fire. The gasifier had average biomass-to-char conversion efficiency of 16.6%. If the produced char is used as fuel, households could save 32% of fuel compared to use of three-stone open fire and 18% when char is used as biochar, for instance. Adoption of the gasifier can help to reduce the need for firewood collection, hence reducing impacts on the environment while saving on the amount of time and money spent on cooking fuel.

Fuel wood is the main source of cooking and heating energy in developing countries. However, it is combusted in inefficient cookstoves, leading to more fuel use and human health problems resulting from exposure to smoke. Thus new, efficient cooking systems that can address some of these problems are required. This study examined gasifier cookstove use in Kwale County, Kenya, and factors influencing adoption. Gasifier stoves were issued for free to 50 households, which were surveyed after 2–3months of use. The results showed that the stove was used by 96% of the households at varying frequencies, 40% of them used it almost every day with 4% switching to only using the new stove. All the users appreciated it because it saved fuel, produced less smoke, and produced charcoal to use for either cooking or soil amendment. Compared with the traditional three-stone open fire, the gasifier stove was reported to be easier to clean (98% of respondents), easier to adjust the heat (88%), easier to handle (58%), caused less exposure to heat (96%) and was cleaner for pots and the kitchen (98%). Another reported benefit of the gasifier stove was that it needed no tending (i.e., adjusting wood and blowing to keep the flames burning). The gasifier stove was mainly used to cook foods that required a short cooking time and many preferred to use it to cook dinner. However, the households encountered some challenges with using the gasifier stoves. For example, fuel preparation, reloading, and lighting were reported as challenges by 42%, 77% and 19%, respectively, of the 83% of households who reported challenges. These challenges could be overcome by improving stove design and by devising innovative ways of cutting fuel into small pieces.

A majority of households in developing countries use biomass energy for cooking and heating due to its affordability and accessibility. However, unsustainable biomass use leads to deforestation, environmental degradation and climate change. The pollution from open burning of biomass is a major health concern especially for women and children as they spend a lot of time in the kitchen. Biochar-producing gasifier cookstoves offer an opportunity to address many of these problems, while also producing biochar, which can be used as a soil amendment. A study was carried out in order to investigate factors influencing the adoption of these cookstoves in three sites in Kenya (Kwale, Embu and Siaya). After an introductory training, 150 households received cookstoves and were asked to use them to produce biochar for upcoming field experiments. User experiences were collected throughsurveys after 2-3 months and about 2 years, and at workshops. The main benefits of the cookstove identified by the users were fuel saving with significant impacts on household economies, reduced smoke and production of biochar for either cooking or soil amendment. Challenges were related to lighting, a need to refill the fuel canister, fuel preparation and different suitability for different typesof meals and meal sizes. The gasifier use frequency and biochar production rates differed between the sites, which had different climate, socio-economic conditions and fuel accessibility. The results will be of relevance for inclusion of user participation in cookstove designing and performance assessment as well as for stakeholders involved in marketing. They can also give guidance on therelevance of gasifier cookstoves for production of biochar for use on farms. (Less)

A majority of people in developing countries use biomass energy for cooking and heating due to its affordability, accessibility and convenience. However, unsustainable biomass use leads to forest degradation and climate change. Therefore, this study was carried out in Kwale County, Kenya, on the use of a biochar-producing gasifier cook stove and implications of its uptake on livelihoods and the environment. Fifty households were trained and issued with a gasifier for free. After 2–3 months of gasifier use, a survey was conducted to investigate the implications of its uptake. The direct impacts included reduced fuel consumption by 38%, reduced time spent in firewood collection, reduced expenditure on cooking fuel, diversification of cooking fuels, improved kitchen conditions and reduced time spent on cooking. The potential benefits included income generation, increased food production, reduced impacts on environment and climate change and reduced health problems. Improved biomass cook stoves can alleviate problems with current cooking methods, which include inefficient fuel use, health issues caused by smoke, and environmental problems. These benefits could contribute to development through alleviating poverty and hunger, promoting gender equality, enhancing good health and sustainable ecosystems and mitigating climate change. The study recommends the promotion of cleaner cooking stoves, particularly gasifiers, among households in rural areas while paying attention to user needs and preferences.