Formation of secondary organic carbon and cloud impact on carbonaceous aerosols at Mount Tai, North China

Zhe Wang, Tao Wang, Jia Guo, Rui Gao, Likun Xue, Jiamin Zhang, Yang Zhou, Xuehua Zhou, Qingzhu Zhang, Wenxing Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

55 Citations (Scopus)

Abstract

Carbonaceous aerosols measured at Mount Tai in north China in 2007 were further examined to study the formation of secondary organic carbon (SOC) and the impact of clouds on carbonaceous species. A constrained EC-tracer method and a multiple regression model showed excellent agreement in estimating SOC concentration. The average concentrations of non-volatile and semi-volatile SOC (SOCNVand SOCSV) were 2.61, 5.58μgm-3in spring and 2.81, 10.44μgm-3in summer. The total SOC accounted for 57.3% and 71.2% of total organic carbon in spring and summer, respectively, indicating the presence of high loading of secondary organic aerosol (SOA) in the North China Plain. The fraction of SOCNVincreased with photochemical age (as indicated by NOx/NOyratios) of air mass, whereas SOCSVwas also influenced by the dynamic equilibrium between formation and sink. Significant scavenging by clouds of non-volatile organic carbon (OCNV) and elemental carbon (EC) was observed, whereas semi-volatile organic carbon (OCSV) concentrations increased during clouds, suggesting substantial SOA formation through aqueous-phase reactions in clouds. A mass balance model was proposed to quantify the scavenging coefficients for OCNV, EC and formation rates of OCSVin clouds. The scavenging coefficient constant of EC (KEC) varied from 0.11 to 0.90h-1, and was higher than that of OCNV(KNV-OC: 0.07-0.55h-1), implying internal mixing of EC with more hygroscopic species. The formation rate constant (JSV-OC) and sink constant (SSV-OC) of OCSVranged from 0.09 to 1.39h-1and 0.001 to 1.07h-1, respectively. These field derived parameters could be incorporated into atmospheric models to help close the gap between predicted and observed SOA loadings in the atmosphere.
Original languageEnglish
Pages (from-to)516-527
Number of pages12
JournalAtmospheric Environment
Volume46
DOIs
Publication statusPublished - 1 Jan 2012

Keywords

  • Carbonaceous aerosol
  • Cloud scavenging
  • In-cloud SOA formation
  • Mount Tai (Mt. Tai)
  • Multiple linear regression
  • Secondary organic aerosol (SOA)

ASJC Scopus subject areas

  • Environmental Science(all)
  • Atmospheric Science

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