title: Emission factors and real-time optical properties of particles emitted from traditional wood burning cookstoves.
abstract: It is estimated that the combustion of biofuel generates 20% of all carbonaceous aerosols, yet these particles are studied less than those of other common sources. We designed and built a portable battery-operated emission-sampling cart to measure the real-time optical properties and other emission characteristics of biofuel cookstoves. In a field study in Honduras, we measured emission factors averaging 8.5 g/kg, higher than those found in previous laboratory studies. Strong flaming events emitted very dark particles with the optical properties of black particles. The elemental carbon to total carbon ratios ranged from 0.07 to 0.64, confirming that high elemental carbon fractions can be emitted from biofuel combustion and may not be used to distinguish fossil-fuel from biofuel sources when cooking is the dominant usage. Absorption Angstrom exponents, representing the dependence of absorption on wavelength, ranged from 1 (black) to 5 (yellow). Strongly absorbing particles with absorption inversely dependent on wavelength were emitted separately from particles with weak absorption and strong wavelength dependence; the latter probably contained conjugated aromatic compounds. Because combustion occurs in distinct phases, different types of carbonaceous aerosols from biofuel combustion are externally mixed at emission and may have different atmospheric fates.
authors.affiliation: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, Illinois 61801, USA. croden@uiuc.edu
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Roden
authors.forename: Tami C
authors.initials: TC
authors.lastname: Bond
authors.forename: Stuart
authors.initials: S
authors.lastname: Conway
authors.forename: Anibal Benjamin Osorto
authors.initials: AB
authors.lastname: Pinel
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution; D016902:Air Pollution, Indoor; D002244:Carbon / Q000737:chemistry*; D002274:Carcinogens, Environmental; D003296:Cooking; D004781:Environmental Exposure; D004784:Environmental Monitoring; D005579:Fossil Fuels; D006721:Honduras; D006794:Household Articles / Q000295:instrumentation*; D006838:Hydrocarbons / Q000032:analysis; D013997:Time Factors; D014934:Wood
chemical_list: D000393:Air Pollutants; D002274:Carcinogens, Environmental; D005579:Fossil Fuels; D006838:Hydrocarbons; D002244:Carbon