Abstract:
Globally, six million deaths annually are attributed to exposure to Indoor air Pollution (IAP) in developing
countries due to pneumonia, chronic respiratory diseases and lung cancer, with the overall disease burden in
Disability Adjusted Life Years (DALYs) exceeding the burden from outdoor air pollution by five-fold. In
Kenya, respiratory infections account for 12% of annual deaths. This is due to overreliance on traditional
biomass fuels which account for 90% of rural households and 70% of urban households as their primary cooking
fuel. The objective of this study was to assess exposure levels to particulate matter (PM) and carbon monoxide
(CO) from biomass fuel use in improved stoves and traditional stoves in Western Kenya region. The data was
collected through continuous real-time monitoring of personal exposure levels for a period of 24 hours using
CO monitors. Algorithms were used to estimate long term and short-term personal exposure of particulate
matter from kitchen concentration levels. 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. At 95% CI, Maximum Daily Intake (MDI) of PM 2.5 was significantly higher using
crop residues compared to wood fuel. Maximum daily intake using mud rocket stove was 889.889 μg/m 3 and
311.725 μg/m 3 using wood and crop residue fuels, respectively. Daily exposureof PM 2.5 using Chepkube stove
was 442.354 μg/m 3 and 3518.6 μg/m 3 using firewood and crop residues fuels, respectively. Three-stone stove
produced the highest daily exposure of 3646.5 μg/m 3 and 2768.5 μg/m 3 using crop residues and firewood fuels,
respectively. Household indoor PM and kitchen concentrations associated with biomass fuel combustion in the
study area exceeded WHO indoor safe limits of 25 μg/m 3 in the short term and 10 μg/m 3 in the long term and
are in the hazardous range for human health. The extremely high kitchen PM 2.5 concentrations suggest that mud
rocket stove and Cheprocket stoves cannot be an intervention for health effects of PM 2.5 which are of most
interest in Household air pollution (HAP). Consequently, it is recommended that programs aiming to reduce
exposure to CO and PM2.5 should focus on measures that result in larger reductions of PM2.5 emissions
especially during burning and peak periods.
