Field-deployable instrumentation for fast measurement of various atmospheric sulfur compounds in the parts per trillion range

A field deployable instrumentation was developed for determining atmospheric dimethyl sulfide (DMS), dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO ₂) and sulfur dioxide (SO₂) using atmospheric pressure ionization mass spectrometry (APIMS) Isotopically labeled analytes were used as internal standards. Detection limits below 1 part per trillion by volume (pptv) (S/N is >5 at 0.5 pptv background level) at one sample per second was achieved. Extensive laboratory studies were conducted to evaluate the instrument's sensitivity and stability as well as to simulate the real time measurements. This dissertation reports data from a first time deployment of the instrumentation at the South Pole in December 1998 and January 1999. Data from this deployment showed that this instrumentation had adequate performance in detecting all four species. In addition, methane sulfinic acid (MESA) was also observed in the atmosphere for first real time. The lowest concentrations of all four species occurred when the temperature inversion was strongest and greatest when the inversion was weakest or absent. This observation implies that the origin of these species is the free troposphere just above the inversion and not from local pollution. The most found concentrations for DMS, DMSO, DMSO₂, MESA and SO ₂ were 0.7, 0.9, 1.2, 0.1 and 9 pptv. These field tests further suggest that our APIMS instrumentation be adequate for determining the fluxes of DMS and SO₂ by eddy correlation technique. Finally, in the South Pole data there was strong evidence that H₂O₂ and HNO ₃ were observed as complexes with CO₃–. This implies that these species could be determined by APIMS if isotopically labeled standards of the species are used and a means of determining the blank is established.