Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 12, 2009 | Published
Journal Article Open

Secondary organic aerosol formation from photooxidation of naphthalene and alkylnaphthalenes: implications for oxidation of intermediate volatility organic compounds (IVOCs)


Current atmospheric models do not include secondary organic aerosol (SOA) production from gas-phase reactions of polycyclic aromatic hydrocarbons (PAHs). Recent studies have shown that primary emissions undergo oxidation in the gas phase, leading to SOA formation. This opens the possibility that low-volatility gas-phase precursors are a potentially large source of SOA. In this work, SOA formation from gas-phase photooxidation of naphthalene, 1-methylnaphthalene (1-MN), 2-methylnaphthalene (2-MN), and 1,2-dimethylnaphthalene (1,2-DMN) is studied in the Caltech dual 28-m3 chambers. Under high-NOx conditions and aerosol mass loadings between 10 and 40 μg m−3, the SOA yields (mass of SOA per mass of hydrocarbon reacted) ranged from 0.19 to 0.30 for naphthalene, 0.19 to 0.39 for 1-MN, 0.26 to 0.45 for 2-MN, and constant at 0.31 for 1,2-DMN. Under low-NOx conditions, the SOA yields were measured to be 0.73, 0.68, and 0.58, for naphthalene, 1-MN, and 2-MN, respectively. The SOA was observed to be semivolatile under high-NOx conditions and essentially nonvolatile under low-NOx conditions, owing to the higher fraction of ring-retaining products formed under low-NOx conditions. When applying these measured yields to estimate SOA formation from primary emissions of diesel engines and wood burning, PAHs are estimated to yield 3–5 times more SOA than light aromatic compounds over photooxidation timescales of less than 12 h. PAHs can also account for up to 54% of the total SOA from oxidation of diesel emissions, representing a potentially large source of urban SOA.

Additional Information

© Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License. Received: 27 November 2008 – Published in Atmos. Chem. Phys. Discuss.: 21 January 2009. Revised: 15 April 2009. Accepted: 23 April 2009. Published: 12 May 2009. This research was funded by the Office of Science (BER), US Department of Energy Grant No. DE-FG02-05ER63983, US Environmental Protection Agency STAR Research Assistance Agreement No. RD-83374901 and US National Science Foundation grant ATM-0432377. This publication has not been formally reviewed by the EPA. The views expressed in this document are solely those of the authors and EPA does not endorse any products mentioned in this publication. The authors would like to thank D. R. Fitz for use of GC/NO2-PAN analyzer, L. D. Yee for assistance with running experiments, and C. E. Jordan for helpful discussion.

Attached Files

Published - Chan2009p4285Atmos_Chem_Phys.pdf


Files (2.2 MB)
Name Size Download all
2.2 MB Preview Download

Additional details

August 20, 2023
October 18, 2023