Articles | Volume 15, issue 5
Research article
10 Mar 2015
Research article |  | 10 Mar 2015

A critical evaluation of proxy methods used to estimate the acidity of atmospheric particles

C. J. Hennigan, J. Izumi, A. P. Sullivan, R. J. Weber, and A. Nenes


Interactive discussion

Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision
AR by Christopher Hennigan on behalf of the Authors (14 Jan 2015)  Author's response   Manuscript 
ED: Publish as is (12 Feb 2015) by Astrid Kiendler-Scharr (deceased)
AR by Christopher Hennigan on behalf of the Authors (17 Feb 2015)
Short summary
We show that the ion balance and molar ratio methods are unsuitable for use as aerosol pH proxies. Our recommendation is that 1) thermodynamic equilibrium models constrained by both gas and aerosol inputs run in the forward (open) mode, and 2) the phase partitioning of ammonia provides the best predictions of aerosol pH. Given the significance of acidity for numerous chemical processes in the atmosphere, the implications of this study are important and far reaching.
Final-revised paper