Assessment of Improved Biomass Cookstove Technologies and Kitchen Characteristics on Indoor Air Quality and Fuel Consumption in Rural Settings of Western, Kenya

Purpose: This study investigated the impact of increased levels of indoor air pollution (IAP) caused due to biomass burning using different technologies in the rural households of Western, Kenya. A comparative assessment of the impact of traditional cookstoves (TCS) and improved cookstoves (ICS) coupled with the characteristics of kitchen was conducted to estimate the PM2.5 and CO concentrations in the micro-environments of kitchen and living area of the households. Methodology: The study incorporated both extensive and intensive real-time indoor air quality (IAQ) monitoring during the two cooking sessions of the day. A multi-stage sampling technique was used in this study and the total target population was 383; where 204 households were selected as the sample size for HH survey and 56 households were selected for indoor air pollution monitoring. Influence of the different types of kitchen characteristics; enclosed, semi-enclosed and open was also comprehensively analyzed to measure its impact on the IAQ. Both UCB-PATS instrument and CO loggers were launched in kitchens for 24 hours. The Kitchen Performance Test (KPT) was applied to demonstrate the effectiveness of stove interventions on household fuel consumption. The pollutant concentrations were reported in terms of 24-h, 1-h peak cooking and long-term time scales. Data was analyzed using Statistical Packages for the Social Sciences (SPSS). Multiple regression analysis was undertaken to evaluate the association between pollutant concentration and kitchen characteristics and to determine a set of variables that best predict the pollutants. Units of analysis included means, standard deviations, minimum values, median values and maximum values and IQR. Spearman’s rank correlation coefficients (r) were used to assess the relationship between mean daily kitchen CO concentrations and kitchen PM2.5 concentrations in order to determine whether all kitchen PM2.5 concentrations were as a result of biomass combustion or there were other microenvironment PM2.5 sources. One-way ANOVA was used to compare the quantified fuel use from different stoves and further multiple tests of mean separation were done according to Tukey’s test of significance at p < 0.05. Findings: The results of the study highlighted that households with improved cookstoves that included the Cheprocket and mud rocket stoves consumed 1.5 kg/day (95% CI: 1.3, 5.8) and 1.3 kg/day (95% CI: 1.2, 5.9) less fuel than households with three-stone stoves respectively. The multiple regression models indicated that well ventilated kitchens (β = 2.556, SE = 1.646, p = .036) using ICS,  with cemented floors (β = -.091, SE = .026, p = .001) using Chepkube stove and higher number of windows (β = -4.475, SE = 2.841, p = .031) using Cheprocket stove;  (β = -.446, SE = .042, p = .030) using rocket stove; (β = -.045, SE = .010, p = .000) using Chepkube stove were associated with lower kitchen PM2.5 concentrations. The study concludes that usage of ICS coupled with efficient designing of the kitchen can improve the overall IAQ of the household along with immense health benefits. Recommendation: Overall, the study emphasized the need of more user education for improved stoves users for behavioural change to reduce PM and CO kitchen concentrations and exposure.