Effects of strengthening the Baltic Sea ECA regulations

Jonson, Jan Eiof; Gauss, Michael; Jalkanen, Jukka-Pekka; Johansson, Lasse

doi:https://doi.org/10.5194/acp-19-13469-2019

Articles | Volume 19, issue 21

https://doi.org/10.5194/acp-19-13469-2019

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

Special issue:

Shipping and the Environment – From Regional to Global...

https://doi.org/10.5194/acp-19-13469-2019

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

Articles | Volume 19, issue 21

Research article

|

05 Nov 2019

Research article |

| 05 Nov 2019

Effects of strengthening the Baltic Sea ECA regulations

Jan Eiof Jonson, Michael Gauss, Jukka-Pekka Jalkanen, and Lasse Johansson

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Final revised paper (published on 05 Nov 2019)
Preprint (discussion started on 28 Feb 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Referee Comment', Anonymous Referee #1, 19 Mar 2019
- RC2: 'Referee comment', Anonymous Referee #3, 23 Mar 2019
  - AC2: 'Reply to reviewer 3', Jan Eiof Jonson, 28 May 2019
- AC1: 'Response to Anonymous Referee #1', Jan Eiof Jonson, 28 May 2019

Peer-review completion

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

AR by Lorena Grabowski on behalf of the Authors (03 Jun 2019) Author's response

ED: Referee Nomination & Report Request started (06 Jun 2019) by Huan Liu

RR by Anonymous Referee #1 (25 Jun 2019)

RR by Anonymous Referee #3 (26 Jun 2019)

Suggestions for revision or reasons for rejection

The authors have addressed the reviewers’ comments and revised the manuscript. Their results demonstrated the influence of Baltic Sea ship emissions on air quality and deposition under the SECA regulations and the NECAs in the future. The additional analyses of SO4 due to ship emissions and changes in ozone for the two seasons provide more comprehensive understanding of the ship emissions impact on air quality. However, I still have a few concerns as described below:

1. Page 6, line 30-34: The results showed that the measured and modeled fraction of SO4 in PM2.5 only increase slightly with the Present_HiSulphur scenario. I suggest the authors provide possible explanations for the linkage between the SECA regulation and changes of SO4 and PM2.5 (Present_HiSulphur-Present_Base).

2. Page 8, line 28-31: The statement “In summer the increase caused by titration around the English channel…..dominates the annual values.” is confusing, as NOx titration leads to ozone reduction. Is the increase of SOMO35 and annual ozone over English Channel contrast to decrease of ozone for the rest BAS caused by reduction of titration? If it is what the authors mean, it would be helpful to clearly state the increase “of ozone” (SOMO35 and annual averaged ozone) and “reduction” of titration.

3. Page 8, line 31-34 & Page 9, line 1-2:
(1) It would be helpful to remind reader by referring the figure in detail for better understanding the discussion. For example, for the paragraph “As shown in Figure 4….are higher in 2030 (but SOMO35 is reduced)”, you can add “(green bar)” to specifically refer the bar in Figure 4.

(2) The statement “In 2030 the additional emissions from BAS shipping…..except Denmark” does not match what Figure 4 shows. This sentence seems to discuss the blue bar (contributions from BAS in 2030) in Figure 4 but all the countries have increased SOMO35 and annually average ozone due to BAS ship emissions in the future, including Denmark. Also, the following sentence “Here average ozone decreases (in contrast to the case in 2016, where SOMO35 increases when adding the emissions from BAS shipping)” is not clear either.

4. Page 10, line 19-25: The authors discussed whether the target set by IMO could be achieved in the future based on the results of this paper. Here the connections between the IMO target and the results of this paper are not clear, given the IMO target described here mainly focus on CO2 emissions and GHG emissions from shipping, while this paper focused on NOx, SO2, and PM2.5. The linkages between IMO target and the findings in this study can be stated more clearly.

Technical comments:
1. Page 3, line 1: Please specify what LNG stands for.
2. Page 17, Table2: The Base-model calculated values of NO2 and SO2 for the site Uto are negative.
3. Page 18, Table2: The HiSulphur-model calculated value of SO4 for the site Rao is negative.
3. Page 23, Figure 4: The figure descriptions and legends are not consistent (green bar should be Present_Base – Future_Base; blue bar should be Future_Base – Future_NoShip).

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ED: Reconsider after major revisions (07 Jul 2019) by Huan Liu

AR by Jan Eiof Jonson on behalf of the Authors (20 Aug 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (21 Aug 2019) by Huan Liu

RR by Anonymous Referee #1 (30 Aug 2019)

RR by Anonymous Referee #3 (01 Sep 2019)

ED: Publish subject to technical corrections (29 Sep 2019) by Huan Liu

AR by Jan Eiof Jonson on behalf of the Authors (08 Oct 2019) Author's response Manuscript

Short summary

Calculations have been made with the regional-scale EMEP chemical transport model covering Europe and the sea areas surrounding Europe, including much of the North Atlantic. The main focus is on the effects on air pollution as well as depositions of sulfur and nitrogen following the implementation of stricter sulfur emission regulations from 1 January 2015 for ships operating in the Baltic Sea. We also include a study on the effects of future (2030) emissions changes.