Science Inventory

Light absorption of organic carbon emitted from burning wood, charcoal and kerosene in household cookstoves

Citation:

Mingjie, X., S. Guofeng, A. Holder, M. Hays, AND Jim Jetter. Light absorption of organic carbon emitted from burning wood, charcoal and kerosene in household cookstoves. ENVIRONMENTAL POLLUTION. Elsevier Science Ltd, New York, NY, 240:60-67, (2018). https://doi.org/10.1016/j.envpol.2018.04.085

Impact/Purpose:

Household cookstove emissions are an important source of carbonaceous aerosols globally. Light absorbing organic carbon, also known as brown carbon, emitted from cookstoves can impact regional visibility, photochemistry, and the earth’s radiative balance. This study investigated the optical and characteristics of emissions from a variety of cookstoves operated on the water boiling test to understand the nature of brown carbon emissions from cookstoves. The mass absorption coefficient, which is the amount of light absorption per unit mass of organic carbon, was dependent upon the fuel type, with red oak combustion have coefficients 2 – 6 times larger than from charcoal or kerosene and 4 times greater than from open biomass burning. Considering the widespread usage of cookstoves globally and the distinct differences in the optical properties from open burning, cookstoves should be treated as a separate emission source in air quality and climate models.

Description:

Household cookstove emissions are an important source of carbonaceous aerosols globally. The light-absorbing organic carbon (OC), also termed brown carbon (BrC), from cookstove emissions can impact the Earth’s radiative balance, but is rarely investigated. In this work, PM2.5 filter samples were collected during combustion experiments with red oak wood, charcoal and kerosene in a variety of cookstoves mainly at two water boiling test phases (cold start CS, hot start HS). Samples were extracted in methanol, and extracts were examined using spectrophotometry. The mass absorption coefficients (MACλ, m2 g-1) at five wavelengths (365, 400, 450, 500 and 550 nm) were used as measurement proxy for BrC. The MAC365 for red oak combustion during the CS phase correlated strongly to elemental carbon (EC)/OC ratio, indicating a dependency of BrC absorption on burn conditions. The emissions from cookstoves burning red oak have an average MACλ 2–6 times greater than those burning charcoal and kerosene, and around 4 times greater than that from open biomass burning measured in previous studies. These results suggest that residential cookstove emissions could contribute largely to ambient BrC, and the simulation of BrC radiative forcing in climate models for biofuel combustion in cookstoves should be treated specifically and separate from open biomass burning.