Short communication Mass absorption efﬁciency of elemental carbon for source samples from residential biomass and coal combustions Guofeng Shen a, b, c , Yuanchen Chen a , Siye Wei a , Xiaofang Fu a , Ying Zhu a , Shu Tao a, * a Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China b Jiangsu Provincial Academy of Environmental Sciences, Nanjing 210036, China c Institute for Climate and Global Change Research, School of Atmospheric Sciences, Nanjing University, Nanjing 210093, China article info Article history: Received 20 February 2013 Received in revised form 18 May 2013 Accepted 28 May 2013 Keywords: Mass absorption efﬁciency Residential combustion source Solid fuel Organic carbon Polycyclic aromatic hydrocarbon abstract Optical properties of particulate matter are of growing concern due to their complex effects on atmo- spheric visibility and local/regional climate change. In this study, mass absorption efﬁciency (MAE) of elemental carbon (EC) was measured for source emission samples obtained from the residential com- bustions of solid fuels using a thermal-optical carbon analyzer. For source samples from residential wood, crop straw, biomass pellet and coal combustions, MAE of EC measured at 650 nm, were 3.1 (2.4 e3.7 as 95% Conﬁdence Interval), 6.6 (5.5e7.6), 9.5 (6.7e12), and 7.9 (4.8e11) m 2 g 1 , respectively. MAE of EC for source sample from the wood combustion was signiﬁcantly lower than those for the other fuels, and MAE of EC for coal briquette appeared to be different from that of raw chunk. MAE values of the investigated source emission samples were found to correlate with OC/EC ratio, and a signiﬁcantly positive correlation was found between MAE and particle-bound polycyclic aromatic hydrocarbons (pPAHs), though pPAHs contributed a relatively small fraction of OC. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Mass absorption efﬁciency (MAE, also referred to as mass absorption cross section) is a widely used parameter character- izing the optical properties of light absorbing particles (Bond and Bergstrom, 2006; Cheng et al., 2011). MAE values of light absorbing particles are widely used by climate modelers to determine solar radiation absorption, and it is also an important parameter used to measure elemental carbon mass concentra- tion with photometric methods (Bond and Bergstrom, 2006; Chung et al., 2012; Liousse et al., 1993; Ram and Sarin, 2009). The term of light-absorbing carbon (LAC) was suggested by Malm et al. (1994) and adopted by Bond and Bergstrom (2006) in their review to avoid conﬂict with operationally based deﬁni- tion. In practice, the light absorbing component has several names, among which, “Black Carbon (BC)” is the most widely used for climate modelers, and “Elemental Carbon (EC)” is widely used in air quality and source apportionment studies by atmospheric chemists (Bond et al., 2004; Bond and Bergstrom, 2006). BC is deﬁned optically, implying that the aerosols have strong absorption across a wide spectrum of wavelengths, and EC is an operational deﬁnition based on the thermal stability of carbon. MAE reported in the literature vary dramatically depending on the source types (e.g., biomass burning or diesel exhaust), particle properties (e.g., size and mixing state) and even measurement methods (e.g., ﬁlter-based or not) (Bond and Bergstrom, 2006; Kanaya et al., 2008; Lan et al., 2013; Ram et al., 2012; Snyder and Schauer, 2007; Weingartner et al., 2003). Once emitted into the atmosphere, MAE values would change obviously (increased in most cases) due to particle coagulation and aggregation, change in mixing status during the aging (Bond and Bergstrom, 2006; Lan et al., 2013; Ram et al., 2010), and also inﬂuenced by ambient meteorological conditions like relative humidity (Cheng et al., 2008; Wehner et al., 2009). Bond and Bergstrom (2006) reviewed published MAE data in the literature, and found that after correc- tion for the measurement wavelength and scattering processes in the ﬁlter medium, most of the reported results for freshly emitted light-absorbing carbon fell in a narrow range of 6.3e8.6 m 2 g 1 (n ¼ 21), and the variability in MAE for ambient LAC is generally greater. Recent, Lan et al. (2013) reported MAE of black carbon measured at 532 nm averaged at 6.5  0.5 m 2 g 1 in South China where main emission source was vehicular emissions, rather than biomass burning. Schwarz et al. (2008) reported a high MAE value * Corresponding author. Tel./fax: þ86 10 62751938. E-mail addresses: taos@pku.edu.cn, taos@urban.pku.edu.cn (S. Tao). Contents lists available at SciVerse ScienceDirect Atmospheric Environment journal homepage: www.elsevier.com/locate/atmosenv 1352-2310/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.atmosenv.2013.05.082 Atmospheric Environment 79 (2013) 79e84