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Title: Formation and aging of secondary organic aerosol from toluene: Changes in chemical composition, 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 secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NO x under different oxidizing conditions. The effects of the oxidizing condition 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 (OS c), and mass yield. The OA oxidation state generally increased during photo-oxidation, and the final OA OS c ranged from –0.29 to 0.16 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 a significantly different saturation concentration. In conclusion, there was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. The Univ. of Texas at Austin, Austin, TX (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States)
  2. Carnegie Mellon Univ., Pittsburgh, PA (United States); Phillips66, Bartlesville, OK (United States)
  3. Georgia Inst. of Technology, Atlanta, GA (United States); TSI, Inc., Shoreview, MN (United States)
  4. Georgia Inst. of Technology, Atlanta, GA (United States)
  5. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  6. Carnegie Mellon Univ., Pittsburgh, PA (United States); Univ. of Patras, Patras (Greece)
Publication Date:
Grant/Contract Number:
SC0007075; DESC0007075
Type:
Published Article
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 15; Journal Issue: 14; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Research Org:
Carnegie Mellon Univ., Pittsburgh, PA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); EPA STAR Program; National Science Foundation (NSF). Major Research Instrumentation; Wallace Research Foundation
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1201024
Alternate Identifier(s):
OSTI ID: 1326380