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ARS Home » Midwest Area » Bowling Green, Kentucky » Food Animal Environmental Systems Research » Research » Publications at this Location » Publication #374412
Research Project: Developing Safe, Efficient and Environmentally Sound Management Practices for the Use of Animal Manure

Location: Food Animal Environmental Systems Research

Title: Characterization of secondary products formed through oxidation of reduced sulfur compounds

Author
item VAN ROOY, PAUL - University Of California
item PURVIS-ROBERTS, KATHLEEN - Claremont Colleges
item Silva, Philip - Phil
item NEE, MATTHEW - Western Kentucky University
item COCKER III, DAVID - University Of California

Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/2020
Publication Date: 7/1/2021
Publication URL: https://handle.nal.usda.gov/10113/7364611
Citation: Van Rooy, P., Purvis-Roberts, K.L., Silva, P.J., Nee, M.J., Cocker III, D.R. 2021. Characterization of secondary products formed through oxidation of reduced sulfur compounds. Atmospheric Environment. 256. Article 118148. https://doi.org/10.1016/j.atmosenv.2020.118148.
DOI: https://doi.org/10.1016/j.atmosenv.2020.118148

Interpretive Summary: Organic sulfur compounds are common emissions from waste management in agriculture. In the atmosphere they are important reactants but the products formed from their reaction and the pathways are not well understood. A series of laboratory studies were conducted to understand the reaction pathways of two of these compounds, dimethylsulfide and dimethyldisulfide. In an environmental chamber, the two sulfur compounds were exposed to atmospheric oxidation conditions with several reactants at concentrations typical of the atmosphere. Carefully constructed experiments reveal that sulfur reactions with molecular oxygen proceed quite rapidly. These reactions between the sulfur compounds and molecular oxygen have been overlooked in previous experiments and explain some of the uncertainties in reaction pathways.

Technical Abstract: Dimethylsulfide (DMS) and dimethyldisulfide (DMDS) are precursors to products, like sulfuric acid and methanesulfonic acid (MSA), which are important to secondary aerosol formation. The formation and yields of particulate MSA and sulfuric acid from the oxidation of reduced sulfur compounds is not well understood. In this study, a 37.5 cubic meter Teflon environmental chamber was utilized to study the oxidation mechanism and aerosol forming potential of DMS and DMDS under dry conditions. Experiments were conducted in both the presence and absence of, using hydroxyl radical, nitrate radical, as well as an oxidant. With initial concentrations of 100 part-per-billion, relatively low for laboratory oxidation experiments, dominated oxidation of the reduced sulfur precursor and resulted in aerosol mass yields of greater than 40%. Hydroxyl radical oxidation of DMS and DMDS in the absence of resulted in aerosol yields of 6% and 13%, respectively, while nitrate radical oxidation in the presence of resulted in yields of 8% and less than 1%, respectively. Evidence of sulfuric acid formation was present during all particle-forming experiments, as was evidence of additional unknown sulfur-containing organic particulate. There was no evidence of MSA formation in the gas- or particle-phase throughout this study. The absence of MSA formation in the presence of has not been reported in previous studies and indicates a lack of understanding of the MSA formation mechanism. The observations made during this chamber study diverge from observations made during previous studies conducted under high precursor and concentrations, emphasizing the importance of atmospherically relevant initial conditions.