In air, oxidation of organosulfur compounds such as dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and methanethiol (MTO) produces methanesulfonic acid (MSA) and sulfur dioxide (SO2), the latter ultimately being converted into sulfuric acid (H2SO4). These two acids are known to form new particles in air in presence of gas phase amines and water vapor. In order to accurately predict the impact of those particles on visibility, health and climate, it is crucial to be able to measure their precursors accurately and quantitatively. Gas phase reduced organosulfur compounds are, however, challenging to measure due to their reactivity and adsorption on surfaces. In this study, we compare two techniques for measurements of gas phase organosulfur compounds: proton-transfer time-of-flight mass spectrometry (PTR-ToF-MS) and a canister/GC-FID method. While the PTR-Tof-MS allows fast and sensitive real-time data to be acquired, it is difficult to measure DMTS in air due its high fragmentation. On the other hand, the canister/GC-FID method can suffer from reactions on surfaces, specifically for MTO. Application of these two techniques to quantification of OSC from an urban ambient sample is also presented.

Measuring reduced organosulfur compounds in air using PTR-ToF-MS and a canister/GC-FID method

251st National Meeting (2016)

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