Using satellite observations of tropospheric NO2 columns to infer long-term trends in US NOx emissions: the importance of accounting for the free tropospheric NO2 background

Silvern, Rachel F.; Jacob, Daniel J.; Mickley, Loretta J.; Sulprizio, Melissa P.; Travis, Katherine R.; Marais, Eloise A.; Cohen, Ronald C.; Laughner, Joshua L.; Choi, Sungyeon; Joiner, Joanna; Lamsal, Lok N.

doi:https://doi.org/10.5194/acp-19-8863-2019

Articles | Volume 19, issue 13

https://doi.org/10.5194/acp-19-8863-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-19-8863-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 13

Research article

|

12 Jul 2019

Research article |

| 12 Jul 2019

Using satellite observations of tropospheric NO₂ columns to infer long-term trends in US NO_x emissions: the importance of accounting for the free tropospheric NO₂ background

Rachel F. Silvern, Daniel J. Jacob, Loretta J. Mickley, Melissa P. Sulprizio, Katherine R. Travis, Eloise A. Marais, Ronald C. Cohen, Joshua L. Laughner, Sungyeon Choi, Joanna Joiner, and Lok N. Lamsal

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Final revised paper (published on 12 Jul 2019)
Preprint (discussion started on 25 Feb 2019)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Review of Silvern et al.', Anonymous Referee #1, 26 Mar 2019
RC2: 'Comments for Silvern et al.', Anonymous Referee #2, 18 Apr 2019
SC1: 'Comments for Silvern et al.', Zhe Jiang, 21 Apr 2019
AC1: 'Response to Reviewers', Rachel Silvern, 24 May 2019
AC2: 'Response to Jiang', Rachel Silvern, 24 May 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Rachel Silvern on behalf of the Authors (24 May 2019) Author's response Manuscript

ED: Publish as is (03 Jun 2019) by Qiang Zhang

AR by Rachel Silvern on behalf of the Authors (03 Jun 2019) Manuscript

Short summary

The US EPA reports a steady decrease in nitrogen oxide (NO_x) emissions from fuel combustion over the 2005–2017 period, while satellite observations show a leveling off after 2009, suggesting emission reductions and related air quality gains have halted. We show the sustained decrease in NO_x emissions is in fact consistent with observed trends in surface NO₂ and ozone concentrations and that the flattening of the satellite trend reflects a growing influence from the non-anthropogenic background.