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Abstract

This dissertation is concerned with aircraft based measurements of sulfur dioxide in the atmosphere and gaseous sulfuric acid measurements in the internal flow of an aircraft gas turbine engine. Both trace gases promote the formation and growth of sulfate aerosol particles which play an important role in the chemistry of the troposphere and perhaps even in climate. An Ion Trap Mass Spectrometer specially adapted for in flight measurements was employed in the aircraft campaign. Several high resolution altitude profiles in polluted and un-polluted tropospheric air were obtained and implications on particle formation and growth was examined. Sulfuric acid was also measured in the simulated internal flow of an aircraft engine with the Ion Trap Mass Spectrometer. The sulfur conversion efficiency ε was determined for three different fuel sulfur contents and two combustor operating conditions. The results suggest that modern aircraft engines have conversion efficiencies in the range of a few percent (2.3 ±1.2 %) and that modern engines have larger conversion efficiencies compared to the old engines. Even such low ε allow the formation and growth of volatile aerosol particles and also sulfuric acid induced soot activation in aircraft wakes, which initiate formation of contrails and perhaps even cirrus clouds