## 3 Results and Discussion
### Potential Implications of Gasifier Cook Stove Uptake
#### 3.3.3 Impacts on the Environment and Climate Challenges  
_a. Reduced emissions from cooking:_ Uptake of the gasifier, which has been reported to produce less smoke than three-stone open fires [23] can reduce the negative environmental impacts of biomass fuel use. The three-stone open fire burns wood inefficiently, turning it into pollutants like CO and particulate matter (PM) [13]. The introduction of improved cook stoves has been reported as an important way of reducing the negative effects on health and environment resulting from burning of biomass [14; 15]. Figure 7: Biochar being applied to soil at Kwale, Kenya. For example, compared with the three-stone open fire, the use of the gasifier in rural Kenya decreased emissions of CO and PM\({}_{2.5}\) by 45% and 90%, respectively [20]. In Ethiopia, there was an estimated 0.45-2.45 tonnes year\({}^{-1}\) reduction in CO emissions per household through the use of improved cooking stoves compared with the traditional three-stone open fire [27]. The use of improved cooking stoves in Khairatpur village in rural India reduced the emissions of various pollutants by 30% [28]. Reduced fuel useCompared with the three-stone open fire, the gasifier was reported to use less fuel by all the households that were using it. With reduced consumption of fuel and diversified use of various types of fuels such as tree and crop residues for cooking by the gasifier, there would be less filling of trees. Reduced collection of forest residues for fuelwood gives time for the forest to regenerate, seedlings to grow and nutrients to be recycled. Higher availability of agricultural residues which can be used for energy can result from higher agricultural productivity when biochar is applied to soil, and could ease pressure on available biomass resources [38]. Reduced emission from charcoal productionThe gasifier produces charcoal as a by-product of the cooking exercise [16]. The use of a similar gasifier by rural households in Kenya had a biomass-to-charcoal conversion efficiency of 20% [20]. In traditional charcoal-making kilns, volatile gases are released into the environment, causing global warming. Much energy is also wasted in the conventional charcoal-making process, and this increases its carbon footprint [39]. In SSA, the traditional earth kilns have wood-to-charcoal conversion efficiencies of 8%-20% [40], and hence use large amounts of wood per unit of charcoal produced. Carbon sequestrationwhen biochar is applied to soil, it remains in the soil longer than untreated crop residues, which decompose rapidly [38]. This way, carbon is sequestered, and climate change mitigated [41]. Biochar application to soils has been found to increase crop productivity, including the production of roots and aboveground residues, and therefore biogenic carbon storage [37]. In a recent life cycle assessment, the gasifier was reported to perform better than the three-stone open fire in terms of climate change impacts, avoiding 89% of the climate change impact caused by the traditional system [42]. It can also potentially offset greenhouse gas emissions caused by the traditional system, hence generating a net carbon credit [42]. Reduced Health Problems  
The gasifier produces less smoke, hence reducing the concentration of pollutants in the kitchen. Smoke from inefficient traditional cooking practices penetrates deep into the lungs of the users, causing a range of chronic diseases which are deadly with chronic or acute health effects, which makes cooking on an open fire indoors one of the world's greatest, but least well-known, killers [43]. However, even though all the households mentioned liking the gasifier because it produces less smoke, only 4% of the households were using it exclusively while the rest combined the various stoves they owned to appropriately meet their cooking needs. However, a complete switch to a new stove can only be achieved if it fully meets households' cooking needs.