Light-absorbing organic carbon from prescribed and laboratory biomass burning and gasoline vehicle emissions.

ABSTRACT: Light-absorbing organic carbon (OC), also termed brown carbon (BrC), from laboratory-based biomass burning (BB) has been studied intensively to understand the contribution of BB to radiative forcing. However, relatively few measurements have been conducted on field-based BB and even fewer measurements have examined BrC from anthropogenic combustion sources like motor vehicle emissions. In this work, the light absorption of methanol-extractable OC from prescribed and laboratory BB and gasoline vehicle emissions was examined using spectrophotometry. The light absorption of methanol extracts showed a strong wavelength dependence for both BB and gasoline vehicle emissions. The mass absorption coefficients at 365?nm (MAC₃₆₅, m² g^-1C) - used as a measurement proxy for BrC - were significantly correlated (p?365 of gasoline vehicle emission samples is 0.62?±?0.76?m²?g^-1C, which is similar in magnitude to the BB samples (1.27?±?0.76?m²?g^-1C). These results suggest that in addition to BB, gasoline vehicle emissions may also be an important BrC source in urban areas.

SUBMITTER: Xie M 

PROVIDER: S-EPMC5544734 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature