Characterization of size-resolved aerosol components using proton induced X-ray emission, inductively coupled plasma optical emission spectrometry and ion chromatography

Size-resolved aerosol monitoring for PM10, PM25, and PM10 was performed to qualify and quantify the elements and ions by using proton induced X-ray emission (PDCE), inductively coupled plasma optical emission spectrometry (ICP-OES), and ion chromatography (IC) analysis. Time-resolved aerosol samplings based on 2-hour and 14-hour intervals were carried out during daytime and nighttime, respectively. Physical and chemical properties of size-resolved aerosols were investigated to characterize air quality in the national park area of Gyeongju, Korea. The PIXIE and ICP-OES methods made elemental mass of Al, Si, S, K, Ca, Ti, Cr, Fe, Sr, and Pb. And ions of Na+, NH4+, Ca2+, Cl-, NO3-, and SO42- were analyzed by the IC method. The mass concentrations of Si, S, Ti, and Pb determined by PIXIE showed relatively good correlation with those determined by ICP-OES. But Fe and Sr had worse correlations with an average R-2 of 0.4703 and 0.4825, respectively. The PIKE method was a good alternative to measure chemical species of Al, Si, S, K, Ca, Ti, Cr, and Pb for size-resolved aerosols except Fe and Sr in this study. The average relative errors of size-resolved elements for 2-hour and 14-hour interval collections were 10.1 +/- 5.7% (0.1-28.3%) and 9.9 +/- 7.7% (1.3-38.4%). Ammonium sulfates (AS), mineral dust (MD), and sea salt (SS) aerosols were reconstructed from the elements determined by PDCE and ICP-OES and ions obtained by IC. The mass concentration of MD was calculated with crustal elements of Al, Si, Ca, Ti, and Fe, which are associated with soil erosion. The average relative error of MD was the lowest value of 0.8% in the PM10 regime and the highest value of 10.0% in the PM1.0 regime. The average relative errors of AS for PM10, PM2.5, and PM1.0 determined by PIKE, ICP-OES, and IC showed relatively lower values of 0.8-5.7%, 1.7-5.9%, and 3.3-8.3%, respectively. The average mass concentrations of AS, MD, and SS of PM10, PM2.5, and PM1.0 except submicron SS determined by PIKE were comparable to those determined by ICP-OES and IC within the acceptable relative errors.