Chemical composition of radiation fog water at Albany, New York, and its relationship to fog microphysics

Abstract

Radiation fog water samples collected at the Albany (NY) County airport show quite low acid content compared with previously published data on fog acidity: the pH ranges from 4.3 to 6.4. This fog water ionic concentration is indicative of low pollution in this area. The leading mechanism responsible for the variability in aqueous concentration of nonvolatile ionic constituents of these fogs is the growth and evaporation of droplets, as reflected by the variation of LWC during the fog evolution. For these reasons the origin and composition of aerosol on which fog droplet condensation takes place is of major importance. Droplet size spectra analysis show that there is a need for improving the collection methods of fog water in order to better describe the chemistry involved, especially to maximize the drop capture efficiency of the collectors and reduce the sampling time for better resolution.