Comparison of Emissions and Residential Exposure from Traditional and Improved Cookstoves in Kenya
Suspended particulate matter and carbon emissions from
the combustion of biomass, in addition to their environmental
consequences, have been causally associated with
the incidence of respiratory and eye infections. Improved
stoves offer the potential for emissions reduction. We
compare the emissions of suspended particulate matter
and carbon monoxide from traditional and improved biofuel
stoves in Kenya under the actual conditions of household
use. 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 that improved (ceramic)
wood-burning stoves reduce daily average suspended
particulate matter concentration by 48% (1822 íg/m3; 95%
C.I. 663-2982) during the active burning period and by
77% (1034 íg/m3; 95% C.I. 466-1346) during the smouldering
phase. Ceramic stoves also reduce the median and the
75th and 95th percentiles of daily emission concentration
during the burning period and the 95th percentile during the
smouldering phase, and therefore shift the overall
emission profile downward. Improved charcoal-burning
stoves also offer reductions in indoor air pollution compared
to the traditional metal stove, but these are not statistically
significant. The greatest reduction in emission concentration
is achieved as a result of transition from wood to
charcoal where mean emission concentrations drop by 87%
(3035 íg/m3; 95% C.I. 2356-3500) during the burning
period and by 92% (1121 íg/m3; 95% C.I. 626-1216) when
smouldering as well as large reductions in the median
and 75th and 95th percentiles. These results indicate that
transition to charcoal, followed by the use of improved
wood stoves, are viable options for reduction of human
exposure to indoor air pollution in many developing nations.
