10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Chemical Composition of Cookstove Emissions: Laboratory Tests and Real-World Use of Traditional and Improved Stoves
ALEXANDRA LAI, Ming Shan, Sierra Clark, Ellison Carter, Kun Ni, Hongjiang Niu, Xudong Yang, Jill Baumgartner, James Schauer, University of Wisconsin-Madison
Abstract Number: 1514 Working Group: Combustion-Generated Aerosols: the Desirable and Undesirable
Abstract Growing toxicological and epidemiologic evidence indicates that the health effects of exposure to fine particulate matter (PM2.5) depend on particles’ chemical composition. Inefficient household biomass combustion is a major contributor to personal air pollution exposures for at least three billion people worldwide. However, field studies of household biomass burning that measure PM2.5 mass do not typically analyze its chemical composition, which is likely to vary due to factors including fuel type, combustion conditions, stove design, and use of multiple stoves. Consequently, more research on the chemical composition of biomass burning emissions in the field, and how this relates to laboratory measurements, is needed.
Here we investigate the effects of stove and fuel types on composition of PM2.5 emissions using both household measurements of real-world stove use and laboratory emissions testing. Field samples were obtained as part of a household energy intervention study in rural Sichuan province, China. Household PM2.5 samples were collected on Teflon filters, which were then analyzed either individually (for mass, black carbon (BC), water-soluble organic carbon (WSOC), and water-soluble ions) or in composites (elements by ICP-MS and organic molecular markers, including levoglucosan and polycyclic aromatic hydrocarbons (PAH), by GC-MS). Samples were selected and grouped/composited based on stove use, measured using real-time temperature data loggers. Stove use categories included exclusive and combined uses of traditional, semi-gasifier, and other non-biomass (liquefied petroleum gas, biogas, or electricity). In laboratory emissions tests, samples were collected on both Teflon and quartz filters and the same analyses were conducted as for the field samples, as well as thermal-optical measurement of organic and elemental carbon.
In the laboratory, PM2.5 emissions from traditional and semi-gasifier stoves were strikingly different: though both were burning wood, the traditional stoves emitted primarily carbonaceous PM2.5, while the semi-gasifier stove emissions were comprised mostly of water-soluble inorganic ions. Preliminary field data reflects similar trends: WSOC and BC account for larger fractions of PM2.5 mass when traditional stoves are used. Additionally, summed PAH concentrations comprised a larger fraction of PM2.5 mass in households that used traditional stoves than in those that did not, by up to an order of magnitude.
Results from this research will describe how stove design affects emissions independently of fuel type and the extent to which laboratory tests translate to real-world use. Stove emissions in the field are frequently different than lab results in terms of PM2.5 mass, but whether this difference also reflects a change in composition has implications for design and implementation of future intervention studies. Going forward, this knowledge will aid in understanding the relationship between changing domestic energy sources and human health outcomes.