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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2017-370
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
09 May 2017
Review status
A revision of this discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Aging and hygroscopicity variation of black carbon particles in Beijing measured by a quasi-atmospheric aerosol evolution study (QUALITY) chamber
Jianfei Peng1,2, Min Hu1,3, Song Guo1,2, Zhuofei Du1, Dongjie Shang1, Jing Zheng1, Jun Zheng2, Limin Zeng1, Min Shao1, Yusheng Wu1, Don Colllins2, and Renyi Zhang1,2 1State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China 100871
2Department of Atmospheric Sciences, Texas A&M University, College Station, Texas, 77843, USA
3Beijing Innovation Center for Engineering Sciences and Advanced Technology, Peking University, Beijing, China
Abstract. Measurements of aging and hygroscopicity variation of black carbon (BC) particles in Beijing were conducted using a 1.2 m3 quasi-atmospheric aerosol evolution study (QUALITY) chamber, which consisted of a bottom flow chamber where ambient air was pulled through continuously and an upper reaction chamber where aging of BC particles occurred. Within the reaction chamber, transmission of the solar ultraviolet irradiation was approximately 50 %–60 %, wall loss of primary gaseous pollutants was negligible, and BC exhibited a half-lifetime about 3–7 hours. Typically, equilibrium for the primary gases, temperature, and relative humidity between the reaction chamber and ambient air was established within 1 hour. Rapid growth of BC particles was observed, with an average total growth of 77 ± 33 nm and average growth rate of 26 ± 11 nm h−1. Secondary organic aerosol (SOA) accounted for more than 90 % of the coating mass. The O / C ratio of SOA was 0.5, lower than the ambient level. The hygroscopic growth factor of BC particles decreased slightly with an initial thin coating layer because of BC reconstruction, but subsequently increased to 1.06–1.08 upon further aging. The κ (kappa) values for BC particles and coating materials were calculated as 0.035 and 0.040 at the subsaturation and supersaturation conditions, respectively, indicating low hygroscopicity of coated SOA on BC particles. Hence, our results indicate that initial photochemical aging of BC particles does not appreciably alter the particle hygroscopicity in Beijing.

Citation: Peng, J., Hu, M., Guo, S., Du, Z., Shang, D., Zheng, J., Zheng, J., Zeng, L., Shao, M., Wu, Y., Colllins, D., and Zhang, R.: Aging and hygroscopicity variation of black carbon particles in Beijing measured by a quasi-atmospheric aerosol evolution study (QUALITY) chamber, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-370, in review, 2017.
Jianfei Peng et al.
Jianfei Peng et al.
Jianfei Peng et al.

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Short summary
Rapid growth of BC particles was observed in Beijing using a new outdoor chamber, with an average growth rate of 26 ± 11 nm h−1. Secondary organic aerosol (SOA) accounted for more than 90 % of the coating mass. The hygroscopic growth factor of BC particles increased to 1.06–1.08 upon aging. The κ (kappa) values for BC particles were calculated as only 0.035, indicating that initial photochemical aging of BC particles does not appreciably alter the particle hygroscopicity in Beijing.
Rapid growth of BC particles was observed in Beijing using a new outdoor chamber, with an...
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