AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Climate Implications of Emissions from Traditional and Improved Cooking Stoves
GEORGES SALIBA, R. Subramanian, Kelsey Bilsback, Christian L'Orange, John Volckens, Michael Johnson, Allen Robinson, Carnegie Mellon University
Abstract Number: 779 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract The radiative effect associated with the use of cooking stove is largely uncertain due to: 1) large differences between field and lab measurements of primary pollutant emissions, such as particulate matter (PM) and black carbon (BC), coupled with the difficulty to extensively and accurately monitor real-time cooking activities, and 2) poorly constrained BC mixing state at the source. We measured real-time particle-phase emission factors and optical properties from thirty-two individual tests, using different combinations of stove types and fuels, to assess the climate impacts of these emissions. The stoves were tested on the firepower sweep protocol, which potentially better covers the wide range of actual cooking practices, and were selected to cover various geographical regions and a broad range of stove designs, from traditional stoves to gasifier stoves. Stoves were categorized into four distinct categories: rocket elbow stoves, improved charcoal stoves, gasifier stoves, and traditional stoves. Traditional stoves had the highest PM emission averaging: 6.6 ± 2.9 g/kg-fuel. The lowest measured emissions were from gasifier stoves, with an average PM of 0.8 ± 0.2 g/kg-fuel. We found no significant PM reductions from the “improved” design of the rocket elbow stove, which averaged 5.7 ± 1.0 g/kg-fuel. To assess the climate implications of our findings, we first characterized the BC mixing state using Mie theory and single-particle mixing state information from a single particle soot photometer. We found that Mie theory (assuming a complete internal mixture) could predict the measured forcing, implying that the size distribution of BC particles and the total PM-to-BC ratio (a measure of coating thickness) at the source, are the best predictors for accurately modeling forcing from cookstoves. Second, we performed a tradeoff analysis and found that the largest climate (and health) benefits were associated with replacing a traditional stove with a gasifier stove, due to their low PM and even lower BC emissions, resulting in predominantly scattering emissions.