Particle growth with photochemical age from new particle formation to haze in the winter of Beijing, China

Biwu Chu, Lubna Dada, Yongchun Liu, Lei Yao, Yonghong Wang, Wei Du, Jing Cai, K. R. Dällenbach, Xuemeng Chen, Pauli Simonen, Ying Zhou, Chenjuan Deng, Yueyun Fu, Rujing Yin, Haiyan Li, Xu Cheng He, Zeming Feng, Chao Yan, Juha Kangasluoma, Federico BianchiJingkun Jiang, Joni Kujansuu, Veli Matti Kerminen, Tuukka Petäjä, Hong He, Markku Kulmala

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)
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Abstract

Secondary aerosol formation in the aging process of primary emission is the main reason for haze pollution in eastern China. Pollution evolution with photochemical age was studied for the first time at a comprehensive field observation station during winter in Beijing. The photochemical age was used as an estimate of the timescale attributed to the aging process and was estimated from the ratio of toluene to benzene in this study. A low photochemical age indicates a fresh emission. The photochemical age of air masses during new particle formation (NPF) days was lower than that on haze days. In general, the strongest NPF events, along with a peak of the formation rate of 1.5 nm (J1.5) and 3 nm particles (J3), were observed when the photochemical age was between 12 and 24 h while rarely took place with photochemical ages less than 12 h. When photochemical age was larger than 48 h, haze occurred and NPF was suppressed. The sources and sinks of nanoparticles had distinct relation with the photochemical age. Our results show that the condensation sink (CS) showed a valley with photochemical ages ranging from 12 to 24 h, while H2SO4 concentration showed no obvious trend with the photochemical age. The high concentrations of precursor vapours within an air mass lead to persistent nucleation with photochemical age ranging from 12 to 48 h in winter. Coincidently, the fast increase of PM2.5 mass was also observed during this range of photochemical age. Noteworthy, CS increased with the photochemical age on NPF days only, which is the likely reason for the observation that the PM2.5 mass increased faster with photochemical age on NPF days compared with other days. The evolution of particles with the photochemical age provides new insights into understanding how particles originating from NPF transform to haze pollution.

Original languageEnglish
Article number142207
Number of pages7
JournalScience of the Total Environment
Volume753
Early online date2020
DOIs
Publication statusPublished - 2021
Publication typeA1 Journal article-refereed

Keywords

  • Condensation sink
  • Haze
  • New particle formation
  • Photochemical aging
  • Pollution evolution

Publication forum classification

  • Publication forum level 2

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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