AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Evaluation of the Emissions Performance of Natural and Forced Draft Cookstoves in Rural Malawi (Field) and Laboratory Settings
Roshan Wathore, Kevin Mortimer, ANDREW GRIESHOP, North Carolina State University
Abstract Number: 543 Working Group: Indoor Aerosols
Abstract Biomass burning cookstoves used by over 3 billion people accounts for 25% of global black carbon (BC) emissions and a huge burden on human health and the environment. A recent proposal to issue credits certifying BC mitigation efforts, such as replacing traditional cookstoves with improved models, depends on having knowledge of achievable BC reductions. To contribute in this initiative, an emission measurement campaign was undertaken in 2 districts of Malawi (Chikhwawa and Balaka) where over 90% of the population is dependent on wood fuel for household energy. Traditional and cleaner burning cookstoves were tested during routine cooking activities in rural households. Improved stoves included 2 forced draft gasifier stoves - Philips HD4012 and ACE-1, and a locally manufactured natural draft clay stove - Chitetezo Mbaula. CO_2, CO, particle light scattering (for PM_2.5) and absorption (from BC) were measured in real-time along with integrated filter samples for PM_2.5 and Organic/Elemental Carbon (OC/EC) analyses.
Fuel based emission factors (EF; g pollutant per kg fuel), were estimated using the carbon balance approach. PM_2.5 EFs for traditional cookstoves averaged 7.8 ± 2.9 g/kg, with the Philips showing roughly 50% reduction (4.1 ± 0.6 g/kg), although far lower EFs (0.8 g/kg ) have been observed in US-EPA laboratory tests using the standard water boiling test (WBT) protocol. In the field, gasifiers indicated highest EC (akin to BC) to total carbon (TC = OC + EC) ratios and lowest single scattering albedos, indicating greater specific climate warming. When accounting for cooking time and wood consumed, gasifiers showed the lowest global warming potential. Frequency distributions of real-time particle properties for gasifier stoves show that few events such as startup and wood addition dominate particle scattering and absorption respectively. The discrepancy between laboratory and field performance will be investigated for the aforementioned cookstoves from standard WBTs and newly developed laboratory protocols.