CONVERSION OF SULFUR-DIOXIDE TO SULFATE DURING THE DA VINCI FLIGHTS

Simultaneous measurements of atmospheric particulate sulfate and SO2 were made by tandem filter sampling during manned balloon flights. The balloon permitted measurement of chemical species evolution while following a given air mass. On the June 8, 1976, flight, the balloon encountered a relatively stagnant air mass, remaining above St. Louis County for most of the day before being carried off by nocturnal winds. Concentrations of sulfate and SO2 remained relatively constant during an eight-hour period. Processes responsible for concentration changes were examined to set bounds upon the oxidation rate of SO2. The data are consistent with an oxidation rate as low as zero and no greater than 4% h-1. © 1979.