You are here:
Chemical composition, structures, and light absorption of N-containing aromatic compounds emitted from burning wood and charcoal in household cookstoves
Citation:
Xie, M., Z. Zhao, A. Holder, M. Hays, X. Chen, G. Shen, J. Jetter, AND Q. Wang. Chemical composition, structures, and light absorption of N-containing aromatic compounds emitted from burning wood and charcoal in household cookstoves. Atmospheric Chemistry and Physics. Copernicus Publications, Katlenburg-Lindau, Germany, , na, (2020).
Impact/Purpose:
Light absorbing carbon, also termed brown carbon, impacts visibility as well as the earth's radiative balance. Burning of biomass fuels in cookstoves is a major source of global brown carbon. Nitrogen containing aromatic compounds are one class of molecular markers that show promise in identifying the sources of atmospheric brown carbon. This study quantifies composition and concentration of nitrogen containing aromatic compounds in cookstove emissions and highlights that many of these compounds may exist in both the gas and particle phases. These results further our understanding of the sources and chemical composition of brown carbon laying the foundation for including brown carbon in emissions inventories.
Description:
N-containing aromatic compounds (NACs) are an important group of light-absorbing molecules in the atmosphere. They are often observed in combustion emissions, but their chemical formulas and structural characteristics remain uncertain. In this study, red oak wood and charcoal fuels were burned in cookstoves using the standard water boiling test (WBT) procedure. Submicron aerosol particles in the cookstove emissions were collected using quartz (Qf) and polytetrafluoroethylene (PTFE) filter membranes positioned in parallel. A back-up quartz filter (Qb) was also installed downstream of the PTFE filter to evaluate the effect of sampling artifact on NACs measurements. Liquid chromatography-mass spectroscopy (LC-MS) techniques identified seventeen NAC chemical formulas in the cookstove emissions. The average concentrations of total NACs in Qb samples (0.37 ± 0.31 – 1.78 ± 0.78 µg m-3) were greater than 50% of that observed in the Qf samples (0.47 ± 0.40 – 3.54 ± 1.63 µg m-3). The Qb to Qf mass ratios of total and individual NACs (total 0.50 – 1.34, individual 0.02 – 2.71) show the NACs volatilizing from the upstream PTFE filter, contributing to the gas-phase NACs adsorbed on Qb, and the identified NACs might have substantial fractions remaining in the gas-phase. Cookstove emissions from red oak or charcoal fuels did not exhibit unique NAC structural features, but the NACs composition in cookstove emissions are different from other sources. Before identifying NACs sources by combining their structural and compositional information, the gas-particle partitioning behaviors of NACs should be further investigated. The average contributions of total NACs to the light absorption of organic matter at λ = 365 nm (1.10 – 2.58%) in Qf samples are much lower than in Qb samples (10.7 – 21.0%). These results suggest that more research is needed to understand the chemical and optical properties of heavier molecular weight entities in particulate matter (e.g., Molecular Weight > 500 Da) and gaseous chromophores.
URLs/Downloads:
CHEMICAL COMPOSITIONS STRUCTURES AND LIGHT ABSORPTION OF N CONTAINING AROMATIC COMPOUNDS EMITTED FROM BURNING WOOD AND CHARCOAL I HOUSEHOLD COOKSTOVES.PDF (PDF, NA pp, 1643.337 KB, about PDF)SUPPLEMENTARY ORD 036888.PDF (PDF, NA pp, 4087.084 KB, about PDF)
https://acp.copernicus.org/articles/20/14077/2020/acp-20-14077-2020.html
