제주도 고산 PM10, PM2.5, PM1.0 중 OC와 EC의 계절별 변화 특성

Abstract

Organic carbon (OC) and elemental carbon (EC) concentrations were determined for <TEX>$PM_{10}$</TEX>, <TEX>$PM_{2.5}$</TEX> and <TEX>$PM_{1.0}$</TEX> aerosols particles collected at Gosan Superstation on Jeju Island from August 2007 to September 2008. Aerosols were collected on quartz filters for 24 hours and then OC and EC were analyzed by TOR/IMPROVED method. Mean concentrations of OC and EC were <TEX>$4.66\;{\mu}g/m^3$</TEX> and <TEX>$1.69\;{\mu}g/m^3$</TEX> for <TEX>$PM_{10}$</TEX>, <TEX>$3.95\;{\mu}g/m^3$</TEX> and <TEX>$1.69\;{\mu}g/m^3$</TEX> for <TEX>$PM_{2.5}$</TEX>, and <TEX>$3.16\;{\mu}g/m^3$</TEX> and <TEX>$1.42\;{\mu}g/m^3$</TEX> for <TEX>$PM_{1.0}$</TEX>, respectively. The concentrations of OC and EC comprised 16.4% and 6.0% of <TEX>$PM_{10}$</TEX>, 22.9% and 9.8% of <TEX>$PM_{2.5}$</TEX>, and 23.0% and 10.0% of <TEX>$PM_{1.0}$</TEX>. OC and EC showed a clear seasonal variation with the highest in winter and the lowest in summer. The correlations between the two were also the best during the winter (<TEX>$R^2$</TEX>=0.87, 0.94, and 0.95 for <TEX>$PM_{10}$</TEX>, <TEX>$PM_{2.5}$</TEX> and <TEX>$PM_{1.0}$</TEX>). The ratio of OC/EC exhibited the maximum (7.24) during an Asian dust event due to an increase of OC, which was possibly derived from soil. The mass fraction of both OC and EC was the highest in fall. When OC and EC concentrations were highly elevated, EC1 (the first EC fraction determined at <TEX>$550^{\circ}C$</TEX>) and pyrolyzed OC (POC) were dominant subcomponents in winter and OC3 (the third OC fraction determined at <TEX>$450^{\circ}C$</TEX>) and POC in spring.