The importance of non-fossil sources in carbonaceous aerosols in a megacity of central China during the 2013 winter haze episode: A source apportionment constrained by radiocarbon and organic tracers

摘要

To determine the causes of a severe haze episode in January 2013 in China, a source apportionment of different carbonaceous aerosols (CAs) was conducted in a megacity in central China (Wuhan, Hubei Province) by using the measurements of radiocarbon and molecular organic tracers. Non-fossil sources (e.g., domestic biofuel combustion and biogenic emissions) were found to be responsible for 62% +/- 5% and 26% +/- 8% of organic carbon (OC) and elemental carbon (EC) components by mass, respectively. Non fossil sources contributed 57% +/- 4% to total CAs in this large-scale haze event, whereas fossil-fuel sources were less dominant (43% +/- 4%). The CAs were composed of secondary organic carbon (SOC; 46% +/- 10%), primary fossil-fuel carbon (29% +/- 4%) and primary biomass-burning carbon (25% +/- 10%). Although SOC was formed mainly from non-fossil sources (70% +/- 4%), the role of fossil precursors was substantial (30% +/- 4%), much higher than at the global scale. Combined measurement of organic tracers and radiocarbon showed that most non-fossil SOC was probably derived from biomass burning during this long-lasting haze episode in central China. (C) 2016 Elsevier Ltd. All rights reserved.