Polycyclic aromatic hydrocarbons (PAHs) are one of major classes of organic pollutants. As semi-volatile organic compounds, PAHs can be transported in the atmosphere and scavenged according to various processes (dry and wet deposition). Atmospheric deposition is an important pathway for the transfer of pollutants from atmosphere to the terrestrial and water surfaces. The objective of this research is to quantify the dry and wet deposition of the atmospheric PAHs in the Kaohsiung coastal area. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were also performed with diagnostic ratios to determine the potential sources of PAHs.
The mean dry and wet deposition fluxes of atmospheric total suspended particles (TSP) during the study period (January-December 2010) were estimated to be 44.3 (6.60-384) and 211 (56.1-738) mg/m2d, respectively. The annual mean total PAH fluxes in dry and wet deposition were 1500 (749-3760) and 8470 (2280-46000) ng/m2d, respectively. Both concentrations and dry deposition fluxes of TSP were much higher during dust storm. During Ghost Month, however, they were comparable with other sampling events. By comparing with literatures, the total PAH concentrations of TSP were relatively low during Ghost Month, suggesting that wind direction and precipitation might be plausible. The ratio of PM2.5/PM10 had a relatively low value during dust storm, indicating that coarse particle might be predominant. In addition, during dust storm, both TSP dry deposition velocity and total PAH dry deposition velocity were higher than other sampling events. Our findings in this study showed that previous attempts in literature to estimate total PAH dry deposition fluxes by using TSP dry deposition velocity and PAH concentrations could lead to overestimate fluxes in the field.
TSP dry deposition fluxes were positively correlated with atmospheric total TSP concentrations and TSP dry deposition velocity, but were correlated negatively with intensity of precipitation. In addition, TSP dry deposition velocity showed a positive correlation with TSP concentrations. Total PAH dry deposition fluxes were correlated positively with atmospheric total particulate concentrations and total PAH dry deposition velocity, but negatively with intensity of precipitation and temperature. However, TSP and total PAH fluxes in wet deposition were both correlated positively with intensity of precipitation. Diagnostic ratios showed that diesel exhaust was the main source of combustion-derived PAHs in the study. HCA and PCA analysis indicated that emissions from the ships and vehicles, and fuel used were the main sources of combustion-derived PAHs, while during special events, such as dust storm and Ghost Month, suggesting a different source of PAHs.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-1226111-200201 |
| Date | 26 December 2011 |
| Creators | Chen, Kuan-Wei |
| Contributors | Youn Yuen, Shu, Chon-Lin, Lee, Shui-Jen, Chen, Jin-Xin, Lai |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1226111-200201 |
| Rights | user_define, Copyright information available at source archive |
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