Comparison of emissions and residential exposure from traditional and improved cookstoves in Kenya

Suspended particulate matter and carbon emissions from the combustion of bi omass, in addition to their environmental consequences, have been causally associated with the incidence of respiratory and eye infections. improved s toves offer the potential for emissions reduction. We compare the emissions of suspended particulate matter and carbon monoxide from traditional and i mproved biofuel stoves in Kenya under the actual conditions of household us e. Data for analysis is from 137 14-h days of continuous real-time emission concentration monitoring in a total of 38 households. Our analysis shows t hat improved (ceramic) wood-burning stoves reduce daily average suspended p articulate matter concentration by 48% (1822 mu g/m(3); 95% C.I. 663-2982) during the active burning period and by 77% (1034 mu g/m(3); 95% C.I. 466-1 346) during the smouldering phase. Ceramic stoves also reduce the median an d the 75th and 95th percentiles of daily emission concentration during the burning period and the 95th percentile during the smouldering phase, and th erefore shift the overall emission profile downward. Improved charcoal-burn ing stoves also offer reductions in indoor air pollution compared to the tr aditional metal stove, but these are not statistically significant. The gre atest reduction in emission concentration is achieved as a result of transi tion from wood to charcoal where mean emission concentrations drop by 87% ( 3035 mu g/m(3); 95% C.I. 2356-3500) during the burning period and by 92% (1 121 mu g/m(3); 95% C.I. 626-1216) when smouldering as well as large reducti ons in the median and 75th and 95th percentiles. These results indicate tha t transition to charcoal, followed by the use of improved wood stoves, are viable options for reduction of human exposure to indoor air pollution in m any developing nations.