Absorptivity of brown carbon in fresh and photo-chemically aged biomass-burning emissions

Autor: R. Saleh, C. J. Hennigan, G. R. McMeeking, W. K. Chuang, E. S. Robinson, H. Coe, N. M. Donahue, A. L. Robinson
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: Atmospheric Chemistry and Physics, Vol 13, Iss 15, Pp 7683-7693 (2013)
Druh dokumentu: article
ISSN: 1680-7316
1680-7324
DOI: 10.5194/acp-13-7683-2013
Popis: Experiments were conducted to investigate light absorption of organic aerosol (OA) in fresh and photo-chemically aged biomass-burning emissions. The experiments considered residential hardwood fuel (oak) and fuels commonly consumed in wild-land and prescribed fires in the United States (pocosin pine and gallberry). Photo-chemical aging was performed in an environmental chamber. We constrained the effective light-absorption properties of the OA using conservative limiting assumptions, and found that both primary organic aerosol (POA) in the fresh emissions and secondary organic aerosol (SOA) produced by photo-chemical aging contain brown carbon, and absorb light to a significant extent. This work presents the first direct evidence that SOA produced in aged biomass-burning emissions is absorptive. For the investigated fuels, SOA is less absorptive than POA in the long visible, but exhibits stronger wavelength-dependence and is more absorptive in the short visible and near-UV. Light absorption by SOA in biomass-burning emissions might be an important contributor to the global radiative forcing budget.
Databáze: Directory of Open Access Journals