Effect of the exclusion of crustal ions

Introduction Conclusions References Tables Figures Back Close Full Screen / Esc This discussion paper is/has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP if available. Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Abstract Effect of the exclusion of crustal ions (Ca 2+ , Mg 2+ , and K +) in estimating water content of PM 2.5 is investigated using a gas/aerosol equilibrium model, SCAPE 2 (Simulating 5 and clean background offshore, Gosan, Korea. Measurement data show higher concentration of all inorganic species at Seoul, up to 5 times higher in average equivalent concentration especially for volatile species. At both sites there were sufficient equivalent fractions of t-NH 3 (total ammonia = NH 3 + NH + 4 to neutralize acidic species such as t-H 2 SO 4 (total sulfuric acid = H 2 SO 4 + SO 2− 4), t-HNO 3 (total nitric acid = HNO 3 + NO − 3) 10 and t-HCl (total hydrochloric acid = HCl+Cl −). t-NH 3 and t-HNO 3 were higher at Seoul while t-H 2 SO 4 was higher at Gosan. With respect to the estimated water content differences between with and without crustal ions, all the samples are classified into 3 cases; increased, decreased, and constant water content. We identified that change in inorganic composition contributes to increase of water content for aqueous aerosols. 15 And those inorganic compositions vary differently according to ambient atmospheric composition. Meanwhile, aerosol phase shifting from the aqueous to solid phase is the main contributor to decrease of water content and binary salt composition change in the solid phase appears as no change of water content.