Chemical characteristics of carbonaceous aerosols during dust storms over Xi'an in China

Xuxiang Li, Junji Cao, Judith Chow, Yongming Han, Shuncheng Lee, John Watson

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)

Abstract

Characterization of carbonaceous aerosols including CC (carbonate carbon), OC (organic carbon), and EC (elemental carbon) were investigated at Xi'an, China, near Asian dust source regions in spring 2002. OC varied between 8.2 and 63.7 μg m-3, while EC ranged between 2.4 and 17.2 μ m-3during the observation period. OC variations followed a similar pattern to EC and the correlation coefficient between OC and EC is 0.89 (n = 31). The average percentage of total carbon (TC, sum of CC, OC, and EC) in PM2.5during dust storm (DS) events was 13.6%, which is lower than that during non-dust storm (NDS) periods (22.7%). CC, OC, and EC accounted for 12.9%, 70.7%, and 16.4% of TC during DS events, respectively. The average ratio of OC/EC was 5.0 in DS events and 3.3 in NDS periods. The OC-EC correlation (R2= 0.76, n = 6) was good in DS events, while it was stronger (R2= 0.90, n = 25) in NDS periods. The percentage of water-soluble OC (WSOC) in TC accounted for 15.7%, and varied between 13.3% and 22.3% during DS events. The distribution of eight carbon fractions indicated that local emissions such as motor vehicle exhaust were the dominant contributors to carbonaceous particles. During DS events, soil dust dominated the chemical composition, contributing 69% to the PM2.5mass, followed by organic matter (12.8%), sulfate (4%), EC (2.2%), and chloride (1.6%). Consequently, CC was mainly entrained by Asian dust. However, even in the atmosphere near Asian dust source regions, OC and EC in atmospheric dust were controlled by local emission rather than the transport of Asian dust.
Original languageEnglish
Pages (from-to)847-855
Number of pages9
JournalAdvances in Atmospheric Sciences
Volume25
Issue number5
DOIs
Publication statusPublished - 1 Dec 2008

Keywords

  • Carbonate carbon
  • Dust storm
  • Elemental carbon
  • Organiccarbon

ASJC Scopus subject areas

  • Atmospheric Science

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