Developing chemical signatures of particulate air pollution in the Pearl RiverDelta region, China
Mei Zheng , Yuan Cheng , Limin Zeng , Yuanhang Zhang
DOI:
Received August 31, 2010,Revised November 19, 2010, Accepted , Available online
Volume 23,2011,Pages 1143-1149
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PM2:5 samples were collected in a regional sampling network with three sites in Hong Kong and four sites in the adjacent inland
Pearl River Delta (PRD) or Guangdong Province during four months/seasons from 2002–2003. Trans-boundary transport between
Hong Kong and the inland PRD is inevitable under the influence of Asian monsoon. In summer, Hong Kong serves as the upwind
site of the inland PRD while during other seasons it is under the influence of continental emissions. Previous studies have recognized
the importance of using chemical signatures to differentiate local vs. regional contributions to air pollutants in Hong Kong such as the
CO/NOx ratio, ratios of different VOC species. In this study, detailed chemical speciation by gas chromatography-mass spectrometry
was performed with PM2:5 samples to identify new chemical signatures to distinguish aerosols in Hong Kong from those from the inland
PRD. Since Hong Kong is not influenced by the continental emissions from the inland PRD during summer, comparison focused on
chemical data obtained from this season for chemical signatures. The new ratios developed from the current study include LCPI/HCPI
ratio of alkanes (0.39 0.02 in Hong Kong vs. 0.78 0.08 in the inland PRD), pyrene to benzo[ghi]perylene ratio (0.97 0.21 in
Hong Kong compared to 0.20 0.06 in the inland PRD), and the ratio of 1,2-benzenedioic acid to 1,4-benzenedioic acid (1.8 0.1 in
Hong Kong vs. 0.6 0.05 in the inland PRD). Results from this study also revealed that Hong Kong was impacted by ship emissions
as reflected by substantially high V/Ni ratio (9 2) while this ratio was about 1–2 at all sites in the inland PRD, which is very close to
typical ratios from residual oil combustion.
