Development and application of a quantification method for water soluble organosulfates in atmospheric aerosols

Abstract

In recent years, organosulfates have been found as a significant component of secondary organic aerosols from both smog chamber experiments and field measurements. In this study, an indirect method was developed to estimate organosulfates in aerosol particles as a whole based on their sulfate functional group. A series of experiments were conducted to optimize and validate the method, and it was then applied to quantify organosulfates in the aerosol samples collected at three sampling characteristic sites in Shenzhen, with one close to a power plant (PP), one at a heavy traffic intersection (HTI), and one on the campus of Harbin Institute of Technology Shenzhen graduate school (HITSZ). On average, the mass concentrations of organic sulfur (S_org) were 1.98, 1.11, 0.25 μgS m^-3 in PP, HTI and HITSZ respectively. The lower bounds of mass concentrations of organosuflates (OM_s-related) were 6.86, 3.85 and 0.86 μg m^-3 and the upper bounds of mass concentrations of organosulfates were 23.05, 12.93 and 2.90 μg m^-3 in PP, HTI and HITSZ respectively. This indicates that primary emissions from coal burning and automobile exhaust can promote the secondary formation of organosulfates in the atmosphere. Overall, the mass concentrations observed in this work were higher than those reported by previous studies.

Keywords: Ion chromatography; Organosulfates; PM(2.5); Quantification.