Developing chemical signatures of particulate air pollution in the Pearl River Delta region, China

• Published in: Journal of environmental sciences (China) 2011-01, Vol.23 (7), p.1143-1149
• Main Authors: Zheng, Mei, Cheng, Yuan, Zeng, Limin, Zhang, Yuanhang
• Format: Article
• Language: English
• Subjects: aerosols; air pollution; Air Pollution - analysis; alkanes; benzo(a)pyrene; chemical signature; chemical speciation; China; Combustion; Deltas; emissions; Environmental Monitoring; gas chromatography-mass spectrometry; Hong Kong; local and regional air pollution; monsoon season; nickel; nitrogen oxides; oils; Particulate Matter - analysis; Pearl River Delta; PM2.5; pollutants; Regional; river deltas; Rivers; Seasons; Signatures; Summer; volatile organic compounds; 中国; 化学信号; 微粒; 挥发性有机化合物; 珠三角; 珠江三角洲地区; 空气污染物; 签名
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/S1001-0742(10)60526-8

PM 2.5 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 PM 2.5 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.