익산지역에서 봄철 비황사기간 중 입경별 대기먼지농도와 이온조성

Abstract

In order to further determine the mass concentration and ion composition of size-segregated particulate matter (PM) during the non-Asian dust storm of spring, <TEX>$PM_{2.5}$</TEX> (fine particle), <TEX>$PM_{10-2.5}$</TEX> (coarse particle), and <TEX>$PM_{over-10}$</TEX> (PM with an aerodynamic diameter larger than <TEX>$10{\mu}m$</TEX>) were collected using a MCI (multi-nozzle cascade impactor) sampler of a three-stage filter pack in the spring season of 2007 in the Iksan area. During the sampling period from 5 April to 21 April, a total of 34 samples for size-segregated PM were collected, and then measured for PM mass concentrations by gravimetric measurements and for water-soluble inorganic ion species by using ion chromatography. Average mass concentrations of <TEX>$PM_{2.5}$</TEX>, <TEX>$PM_{10-2.5}$</TEX>, <TEX>$PM_{over-10}$</TEX> were <TEX>$35.4{\pm}11.5{\mu}g/m^3$</TEX>, <TEX>$13.3{\pm}5.5{\mu}g/m^3$</TEX> and <TEX>$9.5{\pm}4.7{\mu}g/m^3$</TEX>, respectively. On average, <TEX>$PM_{2.5}$</TEX> accounted for 74% of <TEX>$PM_{10}$</TEX>. Compared with the literature from other areas in Korea, the measured concentration of <TEX>$PM_{2.5}$</TEX> were relatively high. Water-soluble inorganic ion fractions in <TEX>$PM_{2.5}$</TEX>, <TEX>$PM_{10-2.5}$</TEX>, and <TEX>$PM_{over-10}$</TEX> were found to be 47.8%, 28.5%, and 14.7%, respectively. Among the water-soluble inorganic ion species, <TEX>$SO_4^{2-}$</TEX>, <TEX>$NO_3^-$</TEX> and <TEX>$NH_4^+$</TEX> were the main components in <TEX>$PM_{2.5}$</TEX>, while <TEX>$NO_3^-$</TEX> dominantly existed in both <TEX>$PM_{10-2.5}$</TEX> and <TEX>$PM_{over-10}$</TEX>. Non-seasalt <TEX>$SO_4^{2-}$</TEX> (nss-<TEX>$SO_4^{2-}$</TEX> and <TEX>$NO_3^-$</TEX> were found to mainly exist as the neutralized chemical components of <TEX>$(NH_4)_2SO_4$</TEX> and <TEX>$NH_4NO_3$</TEX> in fine particles.