Changes to simulated global atmospheric composition resulting from recent revisions to isoprene oxidation chemistry

M. A. H. Khan, Billie-Louise Schlich, Michael E Jenkin, Michael C Cooke, Richard G. Derwent, Jessica L Neu, Carl J. Percival, Dudley E Shallcross*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

7 Citations (Scopus)
11 Downloads (Pure)

Abstract

Recent revisions to our understanding of the oxidation chemistry of isoprene have been incorporated into a well-established global atmospheric chemistry and transport model, STOCHEM-CRI. These revisions have previously been shown to increase the production and recycling of HOx radicals at lower NOx levels characteristic of the remote troposphere. The main aim of this study is to assess the resultant broader changes to atmospheric composition due to the recent revisions to isoprene oxidation chemistry. The impact of the increased isoprene-related HOx recycling is found to be significant on the reduction of volatile organic compounds (VOCs) lifetime, e.g. a decrease in isoprene’s tropospheric burden by ~17%. The analysis of lifetime reduction of the potent greenhouse gas, methane, associated with the increased HOx recycling, suggests its significant lifetime reduction by ~5% in terms of the current literature. The revisions to the isoprene chemistry also reduce the amount of ozone (by up to 10%), but provide a significant increase in NO3 (by up to 30%) over equatorial forested regions, which can alter the oxidizing capacity of the troposphere. The calculated mixing ratios of formic acid are decreased which in turn leads to an increase in the inferred concentrations of Criegee intermediates due to reduced loss through reaction with formic acid (up to 80%) over the dominant isoprene emitting regions.
Original languageEnglish
Article number117914
Number of pages10
JournalAtmospheric Environment
Volume244
DOIs
Publication statusPublished - 1 Jan 2021

Bibliographical note

Funding Information:
DES and MAHK thank NERC (grant code- NE/K004905/1 ), Bristol ChemLabS and the Primary Science Teaching Trust under whose auspices various aspects of this work was supported. CJP and JLN work was carried out at Jet Propulsion Laboratory , California Institute of Technology , under contract with the National Aeronautics and Space Administration (NASA), and was supported by the Upper Atmosphere Research and Tropospheric Chemistry Programs . © 2020 all rights reserved.

Funding Information:
DES and MAHK thank NERC (grant code-NE/K004905/1), Bristol ChemLabS and the Primary Science Teaching Trust under whose auspices various aspects of this work was supported. CJP and JLN work was carried out at Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA), and was supported by the Upper Atmosphere Research and Tropospheric Chemistry Programs. ? 2020 all rights reserved.

Publisher Copyright:
© 2020 Elsevier Ltd

Keywords

  • Isoprene chemistry
  • HOx recycling
  • oxidation cycle
  • atmospheric lifetime
  • equatorial region

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