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 July 28, 2016 | Published
Journal Article Open

Influence of seed aerosol surface area and oxidation rate on vapor wall deposition and SOA mass yields: a case study with α-pinene ozonolysis

Abstract

Laboratory chambers, invaluable in atmospheric chemistry and aerosol formation studies, are subject to particle and vapor wall deposition, processes that need to be accounted for in order to accurately determine secondary organic aerosol (SOA) mass yields. Although particle wall deposition is reasonably well understood and usually accounted for, vapor wall deposition is less so. The effects of vapor wall deposition on SOA mass yields in chamber experiments can be constrained experimentally by increasing the seed aerosol surface area to promote the preferential condensation of SOA-forming vapors onto seed aerosol. Here, we study the influence of seed aerosol surface area and oxidation rate on SOA formation in α-pinene ozonolysis. The observations are analyzed using a coupled vapor–particle dynamics model to interpret the roles of gas–particle partitioning (quasi-equilibrium vs. kinetically limited SOA growth) and α-pinene oxidation rate in influencing vapor wall deposition. We find that the SOA growth rate and mass yields are independent of seed surface area within the range of seed surface area concentrations used in this study. This behavior arises when the condensation of SOA-forming vapors is dominated by quasi-equilibrium growth. Faster α-pinene oxidation rates and higher SOA mass yields are observed at increasing O3 concentrations for the same initial α-pinene concentration. When the α-pinene oxidation rate increases relative to vapor wall deposition, rapidly produced SOA-forming oxidation products condense more readily onto seed aerosol particles, resulting in higher SOA mass yields. Our results indicate that the extent to which vapor wall deposition affects SOA mass yields depends on the particular volatility organic compound system and can be mitigated through the use of excess oxidant concentrations.

Additional Information

© Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License. Received: 29 March 2016. Published in Atmos. Chem. Phys. Discuss.: 4 April 2016 Revised: 6 July 2016. Accepted: 9 July 2016. Published: 28 July 2016. This research was funded by NSF grants 1455588 and AGS-1523500, and US Environmental Protection Agency STAR grant (Early Career) RD-83540301. This publication's contents are solely the responsibility of the grantee and do not necessarily represent the official views of the US EPA. Further, US EPA does not endorse the purchase of any commercial products or services mentioned in the publication. R.C. McVay was supported by a National Science Foundation Graduate Research Fellowship under grant no. DGE-1144469. Edited by: M. Shiraiwa. Reviewed by: two anonymous referees.

Attached Files

Published - acp-16-9361-2016.pdf

Files

acp-16-9361-2016.pdf
Files (1.7 MB)
Name Size Download all
md5:55df4efb359cd338baefd4473ad68806
1.7 MB Preview Download

Additional details

Created:
August 20, 2023
Modified:
October 23, 2023