Observations of SO2 During NOMADSS

Atmospheric sulfur dioxide, SO₂, has both natural and anthropogenic sources. Both oxidation of marine dimethyl sulfide and volcanic emissions contribute to natural levels, while combustion of sulfur containing fuels and industrial processes further contribute to atmospheric concentrations. Here SO₂ measurements from the recent NSF - NOMADSS (Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks) study will be presented. A Thermo Scientific model 43i-TLE SO₂ monitor was placed aboard the NCAR C-130 and provided a rich data set in SO₂ with measurements in environments ranging from the clean troposphere, to both mixed and local sources of industrial SO₂ emissions. Correlations with sulfuric acid concentrations were observed and when combined with OH concentrations, allow sulfuric acid production rates to be calculated for these various environments. The broad extent of the NOMADSS study also allows a comparison of overall SO₂ levels observed over Texas and Alabama to be compared with those made over the Ohio River valley.