|Van Rooy, Paul - University Of California|
|Cocker, David - University Of California|
|Purvis-roberts, Kathleen - Claremont Colleges|
|Silva, Philip - Phil|
Submitted to: American Association for Aerosol Research
Publication Type: Abstract Only
Publication Acceptance Date: 6/27/2016
Publication Date: 10/20/2016
Citation: Van Rooy, P., Cocker, D.R., Purvis-Roberts, K., Silva, P.J. 2016. Investigating secondary aerosol formation from agricultural amines and reduced sulfur compounds. American Association for Aerosol Research. 592.
Technical Abstract: Gas phase amines and reduced sulfur compounds are often co-emitted from agricultural processes. Amines have been recently recognized as potentially major sources of agricultural aerosol formation, while the reduced sulfur compounds are largely ignored. There is a severe lack of knowledge and understanding regarding the interactions that take place between these co-emitted pollutants to form aerosol. As part of a collaboration between University of California - Riverside, Western Kentucky University, and Claremont colleges, environmental chamber experiments were conducted in order to investigate secondary organic aerosol formation and properties from these sources. Trimethylamine (TMA) was injected into the environmental chamber along with a reduced sulfur compound (dimethylsulfide, dimethyldisulfide, methanethiol, or hydrogen sulfide) and the hydroxyl radical for oxidation. The aerosol yields and characteristics from the oxidation of the combination of precursor were much different than aerosol from either the amine or sulfur compound alone. The amine and the sulfurs interacted quickly to form a substantial concentration of aerosol, much greater than the hydroxyl radical oxidation of the individual components. For example, dimethyldisulfide and TMA with the hydroxyl radical formed nearly 900 micrograms per cubic meter of aerosol after three hours, while separately they formed no more than 20 micrograms per cubic meter. In some cases (e.g. TMA and hydrogen sulfide) aerosol volatility remained constant during the experiment while in other cases (e.g. TMA and dimethyldisulfide) aerosol volatility changed with time. Bulk aerosol composition varied with reduced sulfur compound used. TMA with dimethyldisulfide showed large sulfate peaks. Other combinations (e.g. TMA and methanethiol) showed peaks at high mass-to-charge ratios, consistent with oligomer formation. This novel investigation provides important information on agricultural aerosol formation. Knowledge gained through this study may be useful in regional air quality models as well as particulate matter regulations, specifically for large agricultural operations.