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Title: Aging of secondary organic aerosol from small aromatic VOCs. Changes in chemical composition, mass yield, volatility and hygroscopicity

Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form and transform SOA from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NOx. The effects of chemical aging on organic aerosol (OA) composition, mass yield, volatility and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state OSC) and mass yield. The OA oxidation state generally increased during photo-oxidation, and the final OA OS C ranged from -0.29 to 0.45 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have significantly different saturation concentration. There was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [2] ;  [4]
  1. Univ. of Texas, Austin, TX (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States)
  2. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  3. Georgia Inst. of Technology, Atlanta, GA (United States)
  4. Carnegie Mellon Univ., Pittsburgh, PA (United States); Univ. of Patras, Patras (Greece)
Publication Date:
OSTI Identifier:
1198081
Grant/Contract Number:
DESC0007075
Type:
Published Article
Journal Name:
Atmospheric Chemistry and Physics Discussions (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics Discussions (Online); Journal Volume: 14; Journal Issue: 22; Journal ID: ISSN 1680-7375
Publisher:
European Geosciences Union
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF); Wallace Research Foundation, New York, NY (United States)
Country of Publication:
Germany
Language:
English