Molecular formula composition of β-caryophyllene ozonolysis SOA formed in humid and dry conditions

Journal Article · Thu Dec 22 00:00:00 EST 2016 · Atmospheric Environment (1994)

DOI:https://doi.org/10.1016/j.atmosenv.2016.12.031· OSTI ID:1412872

Kundu, Shuvashish ^[1]; Fisseha, Rebeka ^[2]; Putman, Annie L. ^[2]; Rahn, Thomas A.  ^[2]; Mazzoleni, Lynn R. ^[3]

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1. Michigan Technological Univ., Houghton, MI (United States). Dept. of Chemistry; Univ. of Massachusetts, Amherst, MA (United States). Dept. of Chemistry
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. Michigan Technological Univ., Houghton, MI (United States). Dept. of Chemistry; Michigan Technological Univ., Houghton, MI (United States). Atmospheric Science Program

Here, we studied the molecular formula composition of six β-caryophyllene SOA samples using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry under various reaction conditions. The SOA samples were generated in dry or low relative humidity (RH) chamber conditions with or without cyclohexane. All of the studied SOA mass spectra have three distinct clusters of hundreds of negative ions referred to as Group I (100 < m/z < 400), Group II (400 < m/z < 700) and Group III (700 < m/z < 1 000) compounds. C_14-16H_22-28O_2-11, C_28-29H_42-48O_6-16 and C_42-43H_68-70O_14-16 were observed as highly abundant organic compounds in the compound class of Group I, II and III, respectively. The relative intensities of most analytes were higher in humid conditions compared to those in dry conditions, indicating the importance of water-dependent reactions and the catalytic role of water both in the presence and absence of cyclohexane. In addition, molecular formulas with higher average carbon numbers were observed in humid SOA than in dry SOA in the absence of cyclohexane, suggesting a decrease of cleavage reactions in humid condition. This study characterizes β-caryophyllene ozonolysis SOA based on ultrahigh mass resolution and demonstrates the significance of humidity in terms of the molecular distributions and relative abundances of the analytes. We also discuss the possible mechanism for the formation of Group I-III compounds based on the current understanding of SOA formation in the atmosphere.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program; Gordon and Betty Moore Foundation; National Science Foundation (NSF)
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1412872
• Alternate ID(s): OSTI ID: 1398733
• Report Number(s): LA-UR-17-28024
• Journal Information: Atmospheric Environment (1994), Vol. 154, Issue C; ISSN 1352-2310
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
Analytical Chemistry
Earth Sciences
secondary organic aerosols
beta-caryophyllene
ozonolysis
Smog-chamber
SOA
High resolution mass spectrometry
FT-ICR