Light absorption of black carbon aerosol and its enhancement by mixing state in an urban atmosphere in South China

Lan, Zi-Jian; Huang, Xiaofeng; Yu, Kuangyou; Sun, Tian-Le; Zeng, Liangwei; Hu, Min

doi:10.1016/j.atmosenv.2012.12.009

Cited by 100 publications

(61 citation statements)

References 35 publications

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“…The average concentrations of the cloud RES and INT EBC were 84 ± 75, and 198 ± 125 ng m −3 , respectively. A relatively lower contribution of EBC to the aerosol population supports a substantial addition of secondary aerosols during transport to the high-altitude site given that EBC represents far more than ∼ 2 % of the fine particles near the source regions of southern China (Lan et al, 2013;Wu et al, 2013;Zhang et al, 2013). The observed relatively lower fraction of EBC is consistent with the highly aged state of the BCcontaining particles at the high-altitude site rather than at urban and suburban sites, as discussed in Sect.…”

Section: Mass Scavenging Efficiency Of Ebcsupporting

confidence: 71%

The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

et al. 2017

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Abstract. In the present study, a ground-based counterflow virtual impactor (GCVI) was used to sample cloud droplet residual (cloud RES) particles, while a parallel PM 2.5 inlet was used to sample cloud-free or cloud interstitial (cloud INT) particles. The mixing state of black carbon (BC)-containing particles and the mass concentrations of BC in the cloud-free, RES and INT particles were investigated using a single-particle aerosol mass spectrometer (SPAMS) and two aethalometers, respectively, at a mountain site (1690 m a.s.l.) in southern China. The measured BCcontaining particles were extensively internally mixed with sulfate and were scavenged into cloud droplets (with number fractions of 0.05-0.45) to a similar (or slightly lower) extent as all the measured particles (0.07-0.6) over the measured size range of 0.1-1.6 µm. The results indicate the preferential activation of larger particles and/or that the production of secondary compositions shifts the BC-containing particles towards larger sizes. BC-containing particles with an abundance of both sulfate and organics were scavenged less than those with sulfate but limited organics, implying the importance of the mixing state on the incorporation of BCcontaining particles into cloud droplets. The mass scavenging efficiency of BC with an average of 33 % was similar for different cloud events independent of the air mass. This is the first time that both the mixing state and cloud scavenging of BC in China have been reported. Our results would improve the knowledge on the concentration, mixing state, and cloud scavenging of BC in the free troposphere.

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Section: Mass Scavenging Efficiency Of Ebcsupporting

confidence: 71%

The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

et al. 2017

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“…While freshly emitted EC may contain limited coating, atmospheric aging such as coagulation with other particles, condensation of vapors, and in-cloud processing could cause EC to internally mix with other chemical species (e.g., Moffet and Prather, 2009). Cappa et al (2012) and Lan et al (2013) had observed a limited enhancement due to the mixing state of ambient EC, however, other studies confirmed the enhancement effect of internally mixing under various conditions (Wei et al, 2013;Zhang et al, 2008). The internally mixing can result in enhanced absorption by nearly 2-fold and scattering capacity by approximately 10-fold at 80% relative humidity (RH) relative to fresh particles (Zhang et al, 2008).…”

Section: Introductionmentioning

confidence: 91%

Variation of secondary coatings associated with elemental carbon by single particle analysis

Zhang

et al. 2014

Atmospheric Environment

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“…Since the major primary source of BC in urban environment in PRD was proved to be vehicular exhaust (Yuan et al, 2006;Huang et al, 2006;Lan et al, 2013), we performed three roadway tunnel experiments in urban Shenzhen, in order to verify the representativeness of the AAE BC derived from the urban atmosphere. The tunnel air measurement results were presented in Fig.…”

Section: Roadway Tunnel Experimentsmentioning

confidence: 99%

“…The calibrations of PASS-3 for flow rate, laser power, and absorption were conducted following the standard procedures provided by the operational manual, which were also applied in relevant previous studies (Arnott et al, 2000;Lan et al, 2013;Nakayama et al, 2015). Firstly, the flow rate of sample air was calibrated by a soap film flow meter, with the results shown in Table 1; secondly, the laser power for each wavelength was calibrated by a laser power meter and the error in Table 1 indicated the reading difference between the laser power meter and the laser detector inside the instrument; thirdly, the light absorption calibration was performed by measuring highly absorbing NO 2 (200 ppm) at 532 nm.…”

Section: Calibration Of Pass-3mentioning

confidence: 99%

Light absorption of brown carbon aerosol in the PRD region of China

et al. 2016

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Abstract. The strong spectral dependence of light absorption of brown carbon (BrC) aerosol is regarded to influence aerosol's radiative forcing significantly. The Absorption Angstrom Exponent (AAE) method has been widely used in previous studies to attribute light absorption of BrC at shorter wavelengths for ambient aerosols, with a theoretical assumption that the AAE of "pure" black carbon (BC) aerosol equals to 1.0. In this study, the AAE method was applied to both urban and rural environments in the Pearl River Delta (PRD) region of China, with an improvement of constraining the realistic AAE of "pure" BC through statistical analysis of on-line measurement data. A threewavelength photo-acoustic soot spectrometer (PASS-3) and aerosol mass spectrometers (AMS) were used to explore the relationship between the measured AAE and the relative abundance of organic aerosol to BC. The regression and extrapolation analysis revealed that more realistic AAE values for "pure" BC aerosol (AAE BC ) were 0.86, 0.82, and 1.02 between 405 and 781 nm, and 0.70, 0.71, and 0.86 between 532 and 781 nm, in the campaigns of urban winter , urban fall , and rural fall , respectively. Roadway tunnel experiments were conducted and the results further confirmed the representativeness of the obtained AAE BC values for the urban environment. Finally, the average light absorption contributions of BrC (± relative uncertainties) at 405 nm were quantified to be 11.7 % (±5 %), 6.3 % (±4 %), and 12.1 % (±7 %) in the campaigns of urban winter , urban fall , and rural fall , respectively, and those at 532 nm were 10.0 % (±2 %), 4.1 % (±3 %), and 5.5 % (±5 %), respectively. The relatively higher BrC absorption contribution at 405 nm in the rural fall campaign could be reasonably attributed to the biomass burning events nearby, which was then directly supported by the biomass burning simulation experiments performed in this study. This paper indicates that the BrC contribution to total aerosol light absorption at shorter wavelengths is not negligible in the highly urbanized and industrialized PRD region.

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Light absorption of black carbon aerosol and its enhancement by mixing state in an urban atmosphere in South China

Cited by 100 publications

References 35 publications

The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

Variation of secondary coatings associated with elemental carbon by single particle analysis

Light absorption of brown carbon aerosol in the PRD region of China

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