THE PH OF DELIQUESCED SEA-SALT AEROSOL IN POLLUTED MARINE AIR

The pH of deliquesced sea-salt aerosol was derived from the Cl phase p artitioning measured in marine air, corresponding meteorological condi tions, and the thermodynamic properties of HCl. Under moderately pollu ted conditions at Bermuda during spring 1996, calculated sea-salt aero sol pH ranged from the mid-2s to the mid-3s. Cl- and NO3- concentratio ns in the lower half of the sea-salt size distribution were near therm odynamic equilibrium with respect to HClg and HNO3g; shorter aerosol l ifetimes and slower reaction kinetics involving larger aerosol sustain ed moderate phase disequilibria. The active multiphase cycling of HCl buffered sea-salt aerosol pH to approximately the same value across th e particle size spectrum.