ASSESSMENT OF INDOOR AIR POLLUTION, HEALTH IMPLICATIONS AND IMPACTS OF IMPROVED STOVE INTERVENTIONS IN BUNGOMA AND TRANS NZOIA COUNTIES, KENYA

Abstract

The use of biomass fuels poses great threats to environmental degradation and public health accounting for 32% of the total attributable burden of diseases due to indoor air pollution (IAP) in especially Africa. Heavy reliance on biomass fuels for household energy in Kenya makes the country more vulnerable with 90% of the rural population relying on biomass fuels for domestic purposes. The objective of this study was to assess cooking fuel types, efficiency of improved biomass stoves in fuel consumption, indoor air pollution reduction, analyze potential health risks associated with these stoves and assess how kitchen characteristics influence levels of area pollutant concentration in Bungoma and Trans Nzoia Counties, Kenya. The data were collected through kitchen performance testing, continuous real-time monitoring of kitchen pollution concentration for a period of 24 hours using UCB-PATS and CO monitors, questionnaires and time activity budgets. Data analysis was undertaken by first categorizing pollution data and exposure concentrations into three microenvironments then ANOVA done to test for their variations from WHO stipulated safe standards. Multiple regression analysis was undertaken to evaluate the association between pollutant concentration and kitchen characteristics. The study found that households with improved cook stoves that included the Cheprocket and mud rocket stoves consumed 1.5 kg/day (95% CI (Confidence Interval): 1.3, 5.8) and 1.3 kg/day (95% CI: 1.2, 5.9) less fuel than households with three-stone stoves respectively. While households using Chepkube stove consumed 2.7 kg/day (95% CI: 1.2, 3.6) less compared to three-stone stove. Further at 95% CI, mean 24-hr kitchen PM concentrations from all the stoves were significantly higher than the stipulated WHO threshold. Three-stone fire had the highest average 24-hour kitchen PM and CO emissions using firewood at 4272.414 μg/m3 (p = 0.000) and 75.4417 ppm (p < 0.001), respectively, while Chepkube stove had the least at 682.646 μg/m3 (p < 0.001) and 8.7224 ppm (p < 0.001), respectively. Long-term and short-term exposure concentrations were much lower than kitchen concentration although significantly higher than stipulated safe limits for PM2.5. The daily exposure of CO using different stoves were all above the safe limits of 6ppm apart from Chepkube stove which had (5.6 ppm, p < 0.001) and (5.7 ppm, p < 0.001) using wood and crop residues as fuels respectively. Average peak exposures of CO were within WHO safe 60-minute limits of 30ppm for all stoves. Multiple regression models predicted that well ventilated kitchens (B = 2.556, SE = 1.646, p = .036) using Cheprocket stove; (B =1.484, SE = .050, p = .005) using mud rocket stove; (B = .083, SE = 019, p = .000) using Chepkube stove with cemented floors (B = -.091, p = .001) and increased number of windows were negatively associated with PM2.5 while smaller kitchen window size, lack of connectivity to main grid, increased duration in warming water were positively associated with kitchen PM concentrations. The study concluded that, improved biomass stoves provided an overall reduction in pollutant concentration and fuel use compared to three-stone fire but the local innovation Chepkube stove that has been classified as ungraded stove had the highest pollutant reduction and fuel use reduction. In addition, indoor air pollution in rural areas is a real health risk. Consequently, it was recommended that programs aiming to reduce the adverse health impacts of indoor air pollution should focus on measures that result in larger reductions of CO and PM2.5 emissions especially during burning and peak periods.