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Title of article :
Characterization of carbonaceous aerosol by the stepwise-extraction thermal–optical-transmittance (SE-TOT) method
Author/Authors :
Cheng، نويسنده , , Yuan and He، نويسنده , , Ke-bin and Duan، نويسنده , , Fengkui and Du، نويسنده , , Zhenyu and Zheng، نويسنده , , Mei and Ma، نويسنده , , Yong-liang، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2012
Pages :
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Abstract :
Carbonaceous aerosol collected in Beijing, China was characterized by a stepwise-extraction thermal–optical-transmittance (SE-TOT) method which allows for a quantitative separation of organic aerosol into distinct fractions. About 55% of the total organic carbon (OC) could be extracted by a mixture of hexane, methylene chloride and acetone. The extractable OC was further isolated into non-polar, low-polar and high-polar OC which constituted 10%, 23% and 22% of the total OC, respectively. The sum of low-polar and high-polar OC was found to coincide well with the secondary OC predicted by the elemental carbon tracer method, indicating that the low-polar and high-polar OC are strongly associated with secondary organic aerosol. Moreover, it was suggested that high relative humidity could enhance the production of high-polar OC through aqueous-phase reactions, because high-polar OC correlated strongly with oxalate and the ratio of high-polar OC to low-polar OC was significantly higher during the sampling events with high relative humidity (1.23 ± 0.35) comparing with results from the low relative humidity days (0.79 ± 0.23). In addition, the extractable OC was shown to be light-absorbing. The results of this study suggest that the SE-TOT method could provide new insights into the characterization of carbonaceous aerosol.
Keywords :
carbonaceous aerosol , SOA , Brown carbon , Biomass burning
Journal title :
Atmospheric Environment
Journal title :
Atmospheric Environment
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