References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-11-11497-2011

Mass absorption efficiency of elemental carbon and water-soluble organic carbon in Beijing, China

Cheng

¹ He

K.-B.

¹ Zheng

² Duan

F.-K.

¹ Du

Z.-Y.

¹ Ma

Y.-L.

¹ Tan

J.-H.

³ Yang

F.-M.

³ Liu

J.-M.

⁴ Zhang

X.-L.

⁴ Weber

R. J.

⁴ Bergin

M. H.

⁴ ⁵ Russell

A. G.

⁵

State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China

College of Environmental Sciences and Engineering, Peking University, Beijing, China

Key Laboratory of Computational Geodynamics, College of Earth Science, Graduate University of Chinese Academy of Sciences, Beijing, China

School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA

School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA

18 11 2011

11 22 11497 11510

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The mass absorption efficiency (MAE) of elemental carbon (EC) in Beijing was quantified using a thermal-optical carbon analyzer. The MAE measured at 632 nm was 8.45±1.71 and 9.41±1.92 m2 g−1 during winter and summer respectively. The daily variation of MAE was found to coincide with the abundance of organic carbon (OC), especially the OC to EC ratio, perhaps due to the enhancement by coating with organic aerosol (especially secondary organic aerosol, SOA) or the artifacts resulting from the redistribution of liquid-like organic particles during the filter-based absorption measurements. Using a converting approach that accounts for the discrepancy caused by measurements methods of both light absorption and EC concentration, previously published MAE values were converted to the equivalent-MAE, which is the estimated value if using the same measurement methods as used in this study. The equivalent-MAE was found to be much lower in the regions heavily impacted by biomass burning (e.g., below 2.7 m2 g−1 for two Indian cities). Results from source samples (including diesel exhaust samples and biomass smoke samples) also demonstrated that emissions from biomass burning would decrease the MAE of EC. Moreover, optical properties of water-soluble organic carbon (WSOC) in Beijing were presented. Light absorption by WSOC exhibited strong wavelength (λ) dependence such that absorption varied approximately as λ−7, which was characteristic of the brown carbon spectra. The MAE of WSOC (measured at 365 nm) was 1.79±0.24 and 0.71±0.20 m2 g−1 during winter and summer respectively. The large discrepancy between the MAE of WSOC during winter and summer was attributed to the difference in the precursors of SOA such that anthropogenic volatile organic compounds (AVOCs) should be more important as the precursors of SOA in winter. The MAE of WSOC in Beijing was much higher than results from the southeastern United States which were obtained using the same method as used in this study, perhaps due to the stronger emissions of biomass burning in China.

References 1

Alexander, D. T. L., Crozier, P. A., and Anderson, J. R.: Brown carbon spheres in East Asian outflow and their optical properties, Science, 321, 833–836, 2008.

Allen, G. A., Lawrence, J., and Koutrakis, P.: Field validation of a semi-continuous method for aerosol black carbon (Aethalometer) and temporal patterns of summertime hourly black carbon measurements in southwestern PA, Atmos. Environ., 33, 817–823, 1999.

Andreae, M. O. and Crutzen, P. J.: Atmospheric aerosols: biogeochemical sources and role in atmospheric chemistry, Science, 276, 1052–1058, 1997.

Andreae, M. O. and Gelencsér, A.: Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols, Atmos. Chem. Phys., 6, 3131–3148, http://dx.doi.org/10.5194/acp-6-3131-2006doi:10.5194/acp-6-3131-2006, 2006.

Arnott, W. P., Moosmüller, H., Sheridan, P. J., Ogren, J. A., Raspet, R., Slaton, W. V., Hand, J. L., Kreidenweis, S. M., and Collett Jr., J. L.: Photoacoustic and filter-based ambient aerosol light absorption measurements: instrument comparisons and the role of relative humidity, J. Geophys. Res., 108, 4034, http://dx.doi.org/10.1029/2002JD002165doi:10.1029/2002JD002165, 2003.

Babich, P., Davey, M., Allen, G., and Koutrakis, P.: Method comparisons for particulate nitrate, elemental carbon, and PM$_2.5$ mass in seven US cities, J. Air Waste Manage. Assoc., 50, 1095–1105, 2000.

Bergstrom, R. W., Ackerman, T. P., and Richards, L. W.: Optical Properties of particulate elemental carbon. Particulate carbon: atmospheric life cycle, edited by: Wolff, G. T. and Klimisch, R. L., Plenum Press, New York, USA, 43–51, 1982.

Bergstrom, R. W., Pilewskie, P., Russell, P. B., Redemann, J., Bond, T. C., Quinn, P. K., and Sierau, B.: Spectral absorption properties of atmospheric aerosols, Atmos. Chem. Phys., 7, 5937–5943, http://dx.doi.org/10.5194/acp-7-5937-2007doi:10.5194/acp-7-5937-2007, 2007.

Birch, M. E. and Cary, R. A.: Elemental carbon-based method for monitoring occupational exposures to particulate diesel exhaust, Aerosol Sci. Technol., 25, 221–241, 1996.

Bond, T. C.: Spectral dependence of visible light absorption by carbonaceous particles emitted from coal combustion, Geophys. Res. Lett., 28, 4075–4078, http://dx.doi.org/10.1029/2001GL013652doi:10.1029/2001GL013652, 2001.

Bond, T. C. and Bergstrom, R. W.: Light absorption by carbonaceous particles: an investigative review, Aerosol Sci. Technol., 40, 27–67, 2006.

Bond, T. C., Habib, G., and Bergstrom, R. W.: Limitations in the enhancement of visible light absorption due to mixing state, J. Geophys. Res., 111, D20211, http://dx.doi.org/10.1029/2006JD007315doi:10.1029/2006JD007315, 2006.

Bond, T. C., Streets, D. G., Yarber, K. F., Nelson, S. M., Woo, J. H., and Klimont, Z.: A technology-based global inventory of black and organic carbon emissions from combustion, J. Geophys. Res., 109, D14203, http://dx.doi.org/10.1029/2003JD003697doi:10.1029/2003JD003697, 2004.

Cappa, C., Lack, D., Burkholder, J., and Ravishankara, A.: Bias in filter-based aerosol light absorption measurements due to organic aerosol loading: evidence from laboratory measurements, Aerosol Sci. Technol., 42, 1022–1033, 2008a.

Cappa, C. D., Lovejoy, E. R., and Ravishankara, A. R.: Evidence for liquid-like and nonideal behavior of a mixture of organic aerosol components, P. Natl. Acad. Sci. USA, 105, 18687–18691, 2008b.

Chakrabarty, R. K., Moosmüller, H., Garro, M. A., Arnott, W. P., Walker, J., Susott, R. A., Babbitt, R. E., Wold, C. E., Lincoln, E. N., and Hao, W. M.: Emissions from the laboratory combustion of wildland fuels: particle morphology and size, J. Geophys. Res., 111, D07204, http://dx.doi.org/10.1029/2005JD006659doi:10.1029/2005JD006659, 2006.

Chakrabarty, R. K., Moosmüller, H., Chen, L. W. A., Lewis, K., Arnott, W. P., Mazzoleni, C., Dubey, M. K., Wold, C. E., Hao, W. M., and Kreidenweis, S. M.: Brown carbon in tar balls from smoldering biomass combustion, Atmos. Chem. Phys., 10, 6363–6370, http://dx.doi.org/10.5194/acp-10-6363-2010doi:10.5194/acp-10-6363-2010, 2010.

Chan, T. W., Huang, L., Leaitch, W. R., Sharma, S., Brook, J. R., Slowik, J. G., Abbatt, J. P. D., Brickell, P. C., Liggio, J., Li, S. M., and Moosmüller H.: Observations of OM/OC and specific attenuation coefficients (SAC) in ambient fine PM at a rural site in central Ontario, Canada, Atmos. Chem. Phys., 10, 2393–2411, http://dx.doi.org/10.5194/acp-10-2393-2010doi:10.5194/acp-10-2393-2010, 2010.

Chen, Y. and Bond T. C.: Light absorption by organic carbon from wood combustion, Atmos. Chem. Phys., 10, 1773–1787, http://dx.doi.org/10.5194/acp-10-1773-2010doi:10.5194/acp-10-1773-2010, 2010.

Cheng, Y., He, K. B., Duan, F. K., Zheng, M., Ma, Y. L., Tan, J. H., and Du, Z. Y.: Improved measurement of carbonaceous aerosol: evaluation of the sampling artifacts and inter-comparison of the thermal-optical analysis methods, Atmos. Chem. Phys., 10, 8533–8548, http://dx.doi.org/10.5194/acp-10-8533-2010doi:10.5194/acp-10-8533-2010, 2010.

Cheng, Y., He, K. B., Duan, F. K., Zheng, M., Du, Z. Y., Ma, Y. L., and Tan, J. H.: Ambient organic carbon to elemental carbon ratios: influences of the measurement methods and implications, Atmos. Environ., 45, 2060–2066, 2011.

Chen, Y. J., Zhi, G. R., Feng, Y. L., Liu, D. Y., Zhang, G., Li, J., Sheng, G. Y., Fu, J. M.: Measurements of black and organic carbon emission factors for household coal combustion in China: implication for emission reduction, Environ. Sci. Technol., 43, 9495–9500, 2009.

Chow, J. C., Watson, J. G., Pritchett, L. C., Pierson, W. R., Frazier, C. A., and Purcell, R. G.: The DRI Thermal/Optical Reflectance carbon analysis system: description, evaluation and applications in U.S. air quality studies, Atmos. Environ., 27A, 1185–1201, 1993.

Chow, J. C., Watson, J. G., Crow, D., Lowenthal, D. H., and Merrifield, T.: Comparison of IMPROVE and NIOSH carbon measurements, Aerosol Sci. Technol., 34, 23–34, 2001.

Chow, J. C., Watson, J. G., Chen, L. A., Arnott, W. P., and Moosmüller, H.: Equivalence of elemental carbon by thermal/optical reflectance and transmittance with different temperature protocols, Environ. Sci. Technol., 38, 4414–4422, 2004.

Chow, J. C., Watson, J. G., Doraiswamy, P., Chen, L. A., Sodeman, D. A., Lowenthal, D. H., Park, K., Arnott, W. P., and Motallebi, N.: Aerosol light absorption, black carbon, and elemental carbon at the Fresno Supersite, California, Atmos. Res., 93, 874–887, 2009.

Clarke, A., McNaughton, C., Kapustin, V., Shinozuka, Y., Howell, S., Dibb, J., Zhou, J., Anderson, B., Brekhovskikh, V., Turner, H., and Pinkerton, M.: Biomass burning and pollution aerosol over North America: organic components and their influence on spectral optical properties and humidification response, J. Geophys. Res., 112, D12S18, http://dx.doi.org/10.1029/2006JD007777doi:10.1029/2006JD007777, 2007.

Favez, O., Alfaro, S. C., Sciare, J., Cachier, H., and Abdelwahab, M. M.: Ambient measurements of light-absorption by agricultural waste burning organic aerosols, J. Aerosol Sci., 40, 613–620, 2009.

Flowers, B. A., Dubey, M. K., Mazzoleni, C., Stone, E. A., Schauer, J. J., Kim, S. W., and Yoon, S. C.: Optical-chemical-microphysical relationships and closure studies for mixed carbonaceous aerosols observed at Jeju Island; 3-laser photoacoustic spectrometer, particle sizing, and filter analysis, Atmos. Chem. Phys., 10, 10387–10398, http://dx.doi.org/10.5194/acp-10-10387-2010doi:10.5194/acp-10-10387-2010, 2010.

Gelencsér, A., Hoffer, A., Kiss, G., Tombácz, E., Kurdi, R., and Bencze, L.: In-situ formation of light-absorbing organic matter in cloud water, J. Atmos. Chem., 45, 25–33, 2003.

Gustafsson, O., Kruså, M., Zencak, Z., Sheesley, R. J., Granat, L., Engström, E., Praveen, P. S., Rao, P. S. P., Leck, C., and Rodhe, H.: Brown clouds over south Asia: biomass or fossil fuel combustion?, Science, 323, 495–498, 2009.

Hand, J. L., Malm, W. C., Laskin, A., Day, D., Lee, T., Wang, C., Carrico, C., Carrillo, J., Cowin, J. P., Collett, J., and Iedema, M. J.: Optical, physical, and chemical properties of tar balls observed during the Yosemite Aerosol Characterization Study, J. Geophys. Res., 110, D21210, http://dx.doi.org/10.1029/2004JD005728doi:10.1029/2004JD005728, 2005.

Hansen, A. D. A. and Novakov, T.: Real-time measurement of aerosol black carbon during the carbonaceous species methods comparison study, Aerosol Sci. Technol., 12, 194–199, 1990.

Hecobian, A., Zhang, X., Zheng, M., Frank, N., Edgerton, E. S., and Weber, R. J.: Water-soluble organic aerosol material and the light-absorption characteristics of aqueous extracts measured over the Southeastern United States, Atmos. Chem. Phys., 10, 5965–5977, http://dx.doi.org/10.5194/acp-10-5965-2010doi:10.5194/acp-10-5965-2010, 2010.

Hoffer, A., Gelencsér, A., Guyon, P., Kiss, G., Schmid, O., Frank, G. P., Artaxo, P., and Andreae, M. O.: Optical properties of humic-like substances (HULIS) in biomass-burning aerosols, Atmos. Chem. Phys., 6, 3563–3570, http://dx.doi.org/10.5194/acp-6-3563-2006doi:10.5194/acp-6-3563-2006, 2006.

Husain, L., Dutkiewicz, V. A., Khan, A., and Ghauri, B. M.: Characterization of carbonaceous aerosols in urban air, Atmos. Environ., 41, 6872–6883, 2007.

Jacobson, M. Z.: Isolating nitrated and aromatic aerosols and nitrated aromatic gases as sources of ultraviolet light absorption, J. Geophys. Res., 104, 3527–3542, http://dx.doi.org/10.1029/1998JD100054doi:10.1029/1998JD100054, 1999.

Jacobson, M. Z.: Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature, 409, 695–697, 2001.

Jeong, C. H., Hopke, P. K., Kim, E., and Lee, D. W.: The comparison between thermal-optical transmittance elemental carbon and Aethalometer black carbon measured at multiple monitoring sites, Atmos. Environ., 38, 5193–5204, 2004.

Kirchstetter, T. W., Novakov, T., and Hobbs, P. V.: Evidence that the spectral dependence of light absorption by aerosols is affected by organic carbon, J. Geophys. Res., 109, D21208, http://dx.doi.org/10.1029/2004JD004999doi:10.1029/2004JD004999, 2004.

Knox, A., Evans, G. J., Brook, J. R., Yao, X., Jeong, C. H., Godri, K. J., Sabaliauskas, K., and Slowik, J. G.: Mass absorption cross-section of ambient black carbon aerosol in relation to chemical age, Aerosol Sci. Technol., 43, 522–532, 2009.

Krecl, P., Strom, J., and Johansson, C.: Carbon content of atmospheric aerosols in a residential area during the wood combustion season in Sweden, Atmos. Environ., 41, 6974–6985, 2007.

Lack, D. A., Cappa, C. D., Baynard, T., Massoli, P., Covert, D. S., Sierau, B., Bates, T. S., Quinn, P. K., Lovejoy, E. R., and Ravishankara, A. R.: Bias in filter-based aerosol absorption measurements due to organic aerosol loading: evidence from ambient measurements, Aerosol Sci. Technol., 42, 1033–1041, 2008.

Lim, H. J., Turpin, B. J.: Origins of primary and secondary organic aerosol in Atlanta: Results of time-resolved measurements during the Atlanta Supersite experiment, Environ. Sci. Technol., 36, 4489–4496, 2002.

Lim, H. J., Turpin, B. J., Edgerton, E., Hering, S. V., Allen, G., Maring, H., and Solomon, P.: Semicontinuous aerosol carbon measurements: comparison of Atlanta Supersite measurements, J. Geophys. Res., 108, 8419, http://dx.doi.org/10.1029/2001JD001214doi:10.1029/2001JD001214, 2003.

Liousse, C., Cachier, H., and Jennings, S. G.: Optical and thermal measurements of black carbon aerosol content in different environments: variation of the specific attenuation cross-section, sigma (σ), Atmos. Environ., 27A, 1203–1211, 1993.

Lukács, H., Gelencsér, A., Hammer, S., Puxbaum, H., Pio, C., Legrand, M., Kasper-Giebl, A., Handler, M., Limbeck, A., Simpson, D., and Preunkert, S.: Seasonal trends and possible sources of brown carbon based on 2-year aerosol measurements at six sites in Europe, J. Geophys. Res., 112, D23S18, http://dx.doi.org/10.1029/2006JD008151doi:10.1029/2006JD008151, 2007.

Menon, S., Hansen, J., Nazarenko, L., and Luo, Y. F.: Climate effects of black carbon aerosols in China and India, Science, 297, 2250–2253, 2002.

Petzold, A., Schloesser, H., Sheridan, P. J., Arnott, W. P., Ogren, J. A., and Virkkula, A.: Evaluation of multiangle absorption photometry for measuring aerosol light absorption, Aerosol Sci. Technol., 39, 40–51, 2005.

Pöschl, U.: Atmospheric aerosols: composition, transformation, climate and health effects, Angew. Chem. Int. Ed., 44, 7520–7540, 2005.

Pósfai, M., Gelencsér, A., Simonics, R., Arató, K., Li, J., Hobbs, P. V., and Buseck, P. R.: Atmospheric tar balls: particles from biomass and biofuel burning, J. Geophys. Res., 109, D06213, http://dx.doi.org/10.1029/2003JD004169doi:10.1029/2003JD004169, 2004.

Quincey, P., Butterfield, D., Green, D., Coyle, M., and Cape, C. N.: An evaluation of measurement methods for organic, elemental and black carbon in ambient air monitoring sites, Atmos. Environ., 43, 5085–5091, 2009.

Ram, K. and Sarin, M. M.: Absorption coefficient and site-specific mass absorption efficiency of elemental carbon in aerosols over urban, rural, and high-altitude sites in India, Environ. Sci. Technol., 43, 8233–8239, 2009.

Ramanathan, V. and Carmichael, G.: Global and regional climate changes due to black carbon, Nat. Geosci., 1, 221–227, 2008.

Ramanathan, V., Crutzen, P. J., Kiehl, J. T., and Rosenfeld, D.: Aerosols, climate, and the hydrological cycle, Science, 294, 2119–2124, 2001.

Rattigan, O. V., Dirk Felton, H., Bae, M. S., Schwab, J. J., and Demerjian, K. L.: Multi-year hourly PM$_2.5$ carbon measurements in New York: diurnal, day of week and seasonal patterns, Atmos. Environ., 44, 2043–2053, 2010.

Reisinger, P., Wonaschütz, A., Hitzenberger, R., Petzold, A., Bauer, H., Jankowski, N., Puxbaum, H., Chi, X., and Maenhaut, W.: Intercomparison of measurement techniques for black or elemental carbon under urban background conditions in wintertime: influence of biomass combustion, Environ. Sci. Technol., 42, 884–889, 2008.

Rice, J.: Comparison of integrated filter and automated carbon aerosol measurements at research triangle park, North Carolina, Aerosol Sci. Technol., 38, 23–36, 2004.

Sandradewi, J., Prévôt, A. S. H., Weingartner, E., Schmidhauser, R., Gysel, M., and Baltensperger, U.: A study of wood burning and traffic aerosols in an Alpine valley using a multi-wavelength Aethalometer, Atmos. Environ., 42, 101–112, 2008.

Schauer, J. J., Mader, B. T., DeMinter, J. T., Heidemann, G., Bae, M. S., Seinfeld, J. H., Flagan, R, C., Cary, R. A., Smith, D., Huebert, B. J., Bertram, T., Howell, S., Kline, J. T., Quinn, P., Bates, T., Turpin, B., Lim, H. J., Yu, J. Z., Yang, H., and Keywood, M. D.: ACE-Asia intercomparison of a thermal-optical method for the determination of particle-phase organic and elemental carbon, Environ. Sci. Technol., 37, 993–1001, 2003.

Schnaiter, M., Horvath, H., Möhler, O., Naumann, K. H., Saathoff, H., and Schöck, O. W.: UV-VIS-NIR spectral optical properties of soot and soot-containing aerosols, J. Aerosol Sci., 34, 1421–1444, 2003.

Schnaiter, M., Linke, C., Möhler, O., Naumann, K. H., Saathoff, H., Wagner, R., Schurath, U., and Wehner, B.: Absorption amplification of black carbon internally mixed with secondary organic aerosol, J. Geophys. Res., 110, D19204, http://dx.doi.org/10.1029/2005JD006046doi:10.1029/2005JD006046, 2005.

Schnaiter, M., Gimmler, M., Llamas, I., Linke, C., Jäger, C., and Mutschke, H.: Strong spectral dependence of light absorption by organic carbon particles formed by propane combustion, Atmos. Chem. Phys., 6, 2981–2990, http://dx.doi.org/10.5194/acp-6-2981-2006doi:10.5194/acp-6-2981-2006, 2006.

Sharma, S., Brook, J. R., Cachier, H., Chow, J., Gaudenzi, A., and Lu, G.: Light absorption and thermal measurements of black carbon in different regions of Canada, J. Geophys. Res., 107, 4771, http://dx.doi.org/10.1029/2002JD002496doi:10.1029/2002JD002496, 2002.

Shen, G. F., Wang, W., Yang, Y. F., Ding, J. N., Xue, M., Min, Y. J., Zhu, C., Shen, H. Z., Li, W., Wang, B., Wang, R., Wang, X. L., Tao, S., and Russell, A. G.: Emissions of PAHs from indoor crop residue burning in a typical rural stove: emission factors, size distributions, and gas-particle partitioning, Environ. Sci. Technol., 45, 1206–1212, 2011.

Snyder, D. C. and Schauer, J. J.: An inter-comparison of two black carbon aerosol instruments and a semi-continuous elemental carbon instrument in the urban environment, Aerosol Sci. Technol., 41, 463–474, 2007.

Snyder, D. C., Rutter, A. P., Collins, R., Worley, C., and Schauer, J. J.: Insights into the origin of water soluble organic carbon in atmospheric fine particulate matter, Aerosol Sci. Technol., 43, 1099–1107, 2009.

Subramanian, R., Khlystov, A. Y., and Robinson, A. L.: Effect of peak inert-mode temperature on elemental carbon measured using thermal-optical analysis, Aerosol Sci. Technol., 40, 763–780, 2006.

Subramanian, R., Roden, C. A., Boparai, P., and Bond, T. C.: Yellow beads and missing particles: trouble ahead for filter-based absorption measurements, Aerosol Sci. Technol., 41, 630–637, 2007.

Sullivan, A. P., Weber. R. J., Clements, A. L., Turner, J. R., Bae, M. S., and Schauer, J. J.: A method for on-line measurement of water-soluble organic carbon in ambient aerosol particles: results from an urban site, Geophys. Res. Lett., 31, L13105, http://dx.doi.org/10.1029/2004GL019681doi:10.1029/2004GL019681, 2004.

Sun, Y. L., Zhang, Q., Zheng, M., Ding, X., Edgerton, E. S., and Wang, X. M.: Characterization and source apportionment of water-soluble organic matter in atmospheric fine particles (PM$_2.5$) with High-Resolution Aerosol Mass Spectrometry and GC-MS, Environ. Sci. Technol., 45, 4854–4861, 2011.

Turpin, B. J. and Huntzicker, J. J.: Identification of secondary organic aerosol episodes and quantitation of primary and secondary organic aerosol concentrations during SCAQS, Atmos. Environ., 29, 3527–3544, 1995.

Venkataraman, C., Habib, G., Eiguren-Fernandez, A., Miguel, A. H., and Friedlander, S. K.: Residential biofuels in south Asia: carbonaceous aerosol emissions and climate impacts, Science, 307, 1454–1456, 2005.

Wang, Q., Shao, M., Zhang, Y., Wei, Y., Hu, M., and Guo, S.: Source apportionment of fine organic aerosols in Beijing, Atmos. Chem. Phys., 9, 8573–8585, http://dx.doi.org/10.5194/acp-9-8573-2009doi:10.5194/acp-9-8573-2009, 2009.

Wang, Z. H., Bai, Y. H., and Zhang S. Y.: A biogenic volatile organic compounds emission inventory for Beijing, Atmos. Environ., 37, 3771–3782, 2003.

Weber, R. J., Sullivan, A. P., Peltier, R. E., Russell, A., Yan, B., Zheng, M., de Gouw, J., Warneke, C., Brock, C., Holloway, J. S., Atlas, E. L., and Edgerton, E.: A study of secondary organic aerosol formation in the anthropogenic-influenced southeastern United States, J. Geophys. Res., 112, D13302, http://dx.doi.org/10.1029/2007JD008408doi:10.1029/2007JD008408, 2007.

Weingartner, E., Saathoff, H., Schnaiter, M., Streit, N., Bitnar, B., and Baltensperger, U.: Absorption of light by soot particles: determination of the absorption coefficient by means of Aethalometers, J. Aerosol Sci., 34, 1445–1463, 2003.

Wonaschütz, A., Hitzenberger R., Bauer, H., Pouresmaeil, P., Klatzer, B., Caseiro, A., and Puxbaum, H.: Application of the integrating sphere method to separate the contributions of brown and black carbon in atmospheric aerosols, Environ. Sci. Technol., 43, 1141–1146, 2009.

Yang, M., Howell, S. G., Zhuang, J. and Huebert, B. J.: Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China – interpretations of atmospheric measurements during EAST-AIRE, Atmos. Chem. Phys., 9, 2035–2050, http://dx.doi.org/10.5194/acp-9-2035-2009doi:10.5194/acp-9-2035-2009, 2009.

Zhang, J., He, K. B., Shi, X. Y., and Zhao, Y.: Comparison of particle emissions from an engine operating on biodiesel and petroleum diesel, Fuel, 90, 2089–2097, 2011.

Zhang, T., Claeys, M., Cachier, H., Dong, S. P., Wang, W., Maenhaut, W., and Liu, X. D.: Identification and estimation of the biomass burning contribution to Beijing aerosol using levoglucosan as a molecular marker, Atmos. Environ., 42, 7013–7021, 2008.

Zhang, X., Hecobian, A., Zheng, M., Frank, N. H., and Weber R. J.: Biomass burning impact on PM$_2.5$ over the southeastern US during 2007: integrating chemically speciated FRM filter measurements, MODIS fire counts and PMF analysis, Atmos. Chem. Phys., 10, 6839–6853, http://dx.doi.org/10.5194/acp-10-6839-2010doi:10.5194/acp-10-6839-2010, 2010.