Secondary organic aerosol (SOA) is a substantial contributor to atmospheric organic particulate matter; however, its formation via aqueous oxidation reactions is only beginning to be understood. Although the aqueous organic chemistry that drives SOA formation in clouds (SOACld) has now been incorporated into a few photochemical transport models, it is yet unknown to what extent the newly formed organic material remains in the particle-phase after droplet evaporation. This work investigates SOA formation through cloud water chemistry and droplet evaporation. Aqueous hydroxyl radical oxidation and droplet evaporation experiments were conducted using precursors commonly found in cloud water: glycolaldehyde, methylglyoxal, and glyoxal. A new method was used to measure the volatility of the product mixture. The effective vapor pressure, enthalpy of vaporization, and mass yields of SOACld were determined. Aqueous oxidation produced carboxylic acids and oligomers (i.e., small polymers), which are major constituents of atmospheric aerosols. Enhanced yields (e.g., ~50–80% yields from glycolaldehyde) provide evidence for additional chemistry during droplet evaporation. The overall vapor pressure and enthalpy of vaporization of SOACld were ~1E-07 atm and ~70 kJ/mol, respectively, similar to the mix of organic acids identified. Lastly, a substantial decrease in volatility (~ 1E-08 – 1E-16 atm) was observed when glyoxal SOACld products were exposed to sufficient ammonia to form organic salts. These results provide an important insight on the effects that cloud droplet evaporation and neutralization have on SOA formation through cloud processing. This work furthers our understanding of SOACld formation, and provides measurements that are needed for accurate prediction of SOA in global and regional air quality models.
Subject (authority = RUETD)
Topic
Environmental Sciences
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Rutgers University. Graduate School - New Brunswick
AssociatedObject
Type
License
Name
Author Agreement License
Detail
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.