Aerosol pH and Ion Activities of HSO₄^- and SO₄^2- in Supersaturated Single Droplets.

ABSTRACT: Accurate determination of acidity (pH) and ion activities in aqueous droplets is a major experimental and theoretical challenge for understanding and simulating atmospheric multiphase chemistry. Here, we develop a ratiometric Raman spectroscopy method to measure the equilibrium concentration of sulfate (SO₄^2-) and bisulfate (HSO₄^-) in single microdroplets levitated by aerosol optical tweezers. This approach enables determination of ion activities and pH in aqueous sodium bisulfate droplets under highly supersaturated conditions. The experimental results were compared against aerosol thermodynamic model calculations in terms of simulating aerosol ion concentrations, ion activity coefficients, and pH. We found that the Extended Aerosol Inorganics M

SUBMITTER: Li M 

PROVIDER: S-EPMC9494740 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature