151. Vertical evolution of black and brown carbon during pollution events over North China Plain
- Author
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Yang Sun, Guiqian Tang, Yanyu Kang, Jinyuan Xin, Chongshui Gong, Qinglu Wang, Yinghong Wang, Lili Wang, Mingge Li, Shuang Wu, Jinhui Gao, Jingda Liu, Yuesi Wang, Tingting Li, and Yang Yang
- Subjects
Pollution ,Aerosols ,Air Pollutants ,China ,Environmental Engineering ,Ozone ,Particle number ,media_common.quotation_subject ,Effects of high altitude on humans ,Atmospheric sciences ,Carbon ,chemistry.chemical_compound ,Altitude ,chemistry ,Environmental Chemistry ,Environmental science ,Humans ,Particulate Matter ,Absorption (electromagnetic radiation) ,Waste Management and Disposal ,Air quality index ,Morning ,media_common ,Environmental Monitoring - Abstract
The vertical distribution of carbonaceous aerosol impacts climate change, air quality and human health, but there is a lack of in-situ vertical observations of black (BC) and brown carbon (BrC). Thus, the characteristic of vertical profiles of BC concentration, particle number concentration (PNC), O3 concentration and optical absorption of BC and BrC were observed in a suburban site over North China Plain, where heavy pollution of PM2.5 and O3 always occurred in winter and summer, respectively. In winter, during a heavy pollution episode, the BC and PNC was near uniformly distributed within mixing layer (ML) (15.2 ± 6.7 μg m−3 and 678 ± 227 p cm−3, respectively) and decreased with altitude above the ML. The BC heating rate reached about 0.13 K h−1 during the heaviest pollution day. In summer, the BC concentration (2.9 ± 1.3 μg m−3) in ML during the middle O3 pollution events was higher than that (1.7 ± 0.6 μg m−3) during the light O3 pollution. The light absorption coefficients of BC at 880 nm and BrC at 375 nm measured in the early morning were lower than that in the daytime, and the contribution of BrC to total light absorption of carbonaceous aerosols was in the range of 27–47%. In addition, BC was effectively transported to high altitude than BrC in the daytime. The light absorption of secondary BrC in the daytime was higher 10–20% than that in the early morning. Simultaneously, the contribution of secondary BrC to the total BrC light absorption at 375 nm was range from 32% to 68% within 1000 m.
- Published
- 2021