Particle and Aerosol Research Vol. 9, No. 2, June 2013 |
ISSN : 1738-8716 (Print) ISSN : 2287-8130 (Online) |
Investigation of Chemical Characteristics of PM2.5 during Winter in Gwangju
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Abstracts
24-hr PM2.5 samples were collected from January 19 through February 27, 2009 at an urban site of Gwangju and analyzed to determine the concentrations of organic and elemental carbon(OC and EC), water-soluble OC(WSOC), eight ionic species(Na+, NH4+, K+, Ca2+, Mg2+, Cl-, NO3- and SO42-), and 22 elemental species. Haze phenomena was observed during approximately 29%(10 times) of the whole sampling period(35 days), resulting in highly elevated concentrations of PM2.5 and its chemical components. An Asian dust event was also observed, during which PM2.5 concentration was 64.5 §¶/§©. Crustal materials during Asian dust event contributed 26.6% to the PM2.5, while lowest contribution(5.1%) was from the haze events. OC/EC and WSOC/OC ratios were found to be higher during haze days than during other sampling days, reflecting an enhanced secondary organic aerosol production under the haze conditions. For an Asian dust event, enhanced concentrations of OC and secondary inorganic components were also found, suggesting the further atmospheric processing of precursor gases during transport of air mass to the sampling site. Correlations among WSOC, EC, NO3-, SO42-, and primary and secondary OC fractions, which were predicted from EC tracer method, suggests that the observed WSOC could be formed from similar formation processes as those of secondary organic aerosol, NO3-, and SO42-. Results from principal component analysis indicate also that the observed WSOC was strongly associated with formation routes of the secondary organic and inorganic aerosols.
Keywords£ºHaze, Asian dust, PM2.5, SOA, secondary inorganic species, PCA
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