Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle

Timonen, Hilkka; Karjalainen, Panu; Saukko, Erkka; Saarikoski, Sanna; Aakko-Saksa, Päivi; Simonen, Pauli; Murtonen, Timo; Dal Maso, Miikka; Kuuluvainen, Heino; Bloss, Matthew; Ahlberg, Erik; Svenningsson, Birgitta; Pagels, Joakim; Brune, William H.; Keskinen, Jorma; Worsnop, Douglas R.; Hillamo, Risto; Rönkkö, Topi

doi:https://doi.org/10.5194/acp-17-5311-2017

Articles | Volume 17, issue 8

https://doi.org/10.5194/acp-17-5311-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-17-5311-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 17, issue 8

Research article

|

24 Apr 2017

Research article |

| 24 Apr 2017

Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle

Hilkka Timonen, Panu Karjalainen, Erkka Saukko, Sanna Saarikoski, Päivi Aakko-Saksa, Pauli Simonen, Timo Murtonen, Miikka Dal Maso, Heino Kuuluvainen, Matthew Bloss, Erik Ahlberg, Birgitta Svenningsson, Joakim Pagels, William H. Brune, Jorma Keskinen, Douglas R. Worsnop, Risto Hillamo, and Topi Rönkkö

Download

Final revised paper (published on 24 Apr 2017)
Supplement to the final revised paper
Preprint (discussion started on 26 Sep 2016)
Supplement to the preprint

Interactive discussion

Status: closed

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

- Printer-friendly version

- Supplement

RC1: 'Reviewer comments', Anonymous Referee #2, 23 Oct 2016
RC2: 'Referee comment on "Influence of fuel ethanol ..."', Anonymous Referee #3, 25 Oct 2016
RC3: 'Review of Timonen et al', Anonymous Referee #1, 27 Oct 2016
AC1: 'Response to referee comments', Hilkka Timonen, 31 Jan 2017

Peer-review completion

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

AR by Hilkka Timonen on behalf of the Authors (07 Feb 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (14 Feb 2017) by Delphine Farmer

RR by Anonymous Referee #2 (24 Feb 2017)

RR by Anonymous Referee #1 (24 Feb 2017)

Suggestions for revision or reasons for rejection

The revised manuscript is improved from the previous submission. The authors addressed all of my comments from the previous version, and I find the revised submission easier to read and follow. There are still some organizational issues for the authors to deal with, particularly with the Supplementary Material. I have several comments below:

1. The figures and tables in the Supplement are not presented in order (e.g., Figure S6 is after Figure S22). This needs to be fixed.

2. Section 3.5 - This section would be much more understandable if there was a direct comparison between measured and predicted SOA. I can find the Supplement tables and figures showing the SOA predictions, but these are not directly compared to the measurements. Thus it is not clear if the predicted SOA is larger or smaller than measured SOA for each of the fuels.

Line 38 of page 12 states that the predicted SOA is shown in Figs S20-S22, but this does not seem to be the case. Those figures seem to show measurements after the PAM, but not predicted SOA.

Overall, I'm not sure how important this section is to the manuscript. If the goal of the section is to show that there is poor agreement between measured and predicted SOA when considering only VOC precursors, that seems outside of the scope of this manuscript and is a topic that has been covered extensively in other manuscripts. If the goal is to argue that observed SOA decreases for E85 and E100 because of lower aromatic emissions, the argument is not communicated clearly.

3. Page 4, last sentence in first paragraph (~line 15) - does the sentence about BTEX refer to BTEX emissions or oxidation of BTEX species in the atmosphere?

4. Page 7, Line 28, sentence ending in "regal black" - please clarify that regal black is sometimes used to calibrate the SP-AMS. I don't think it was mentioned previously.

5. The discussion of reasons for higher observed rBC after the PAM in section 3.3.2 is improved. However, this section could benefit from being parsed into multiple paragraphs.

Hide

ED: Reconsider after minor revisions (Editor review) (27 Feb 2017) by Delphine Farmer

Dear Authors:
Pending resubmission with all of the following corrections, I will reconsider after minor revisions.

1. The figures and tables in the Supplement are not presented in order (e.g., Figure S6 is after Figure S22). This needs to be fixed.

2. Section 3.5 - This section would be much more understandable if there was a direct comparison between measured and predicted SOA. I can find the Supplement tables and figures showing the SOA predictions, but these are not directly compared to the measurements. Thus it is not clear if the predicted SOA is larger or smaller than measured SOA for each of the fuels. Please revise the Supplement to make this clear.

Line 38 of page 12 states that the predicted SOA is shown in Figs S20-S22, but this does not seem to be the case. Those figures seem to show measurements after the PAM, but not predicted SOA. Please clarify.

Overall, I'm not sure how important this section is to the manuscript. If the goal of the section is to show that there is poor agreement between measured and predicted SOA when considering only VOC precursors, that seems outside of the scope of this manuscript and is a topic that has been covered extensively in other manuscripts. If the goal is to argue that observed SOA decreases for E85 and E100 because of lower aromatic emissions, the argument is not communicated clearly. Please clarify.

3. Page 4, last sentence in first paragraph (~line 15) - does the sentence about BTEX refer to BTEX emissions or oxidation of BTEX species in the atmosphere?

4. Page 7, Line 28, sentence ending in "regal black" - please clarify that regal black is sometimes used to calibrate the SP-AMS. I don't think it was mentioned previously.

5. The discussion of reasons for higher observed rBC after the PAM in section 3.3.2 is improved. However, this section could benefit from being parsed into multiple paragraphs.

6. The authors have measured the particle wall loss rate as a function of the particle size. The derived wall loss rates need to be applied to the measured raw particle distribution during each PAM experiment to yield the wall loss corrected organic aerosol masses.

Hide

AR by Hilkka Timonen on behalf of the Authors (08 Mar 2017) Author's response Manuscript

ED: Publish subject to technical corrections (24 Mar 2017) by Delphine Farmer

AR by Hilkka Timonen on behalf of the Authors (28 Mar 2017) Author's response Manuscript

Download

Article (6983 KB)
Full-text XML

Short summary

The effect of fuel ethanol content (10–100 %) on primary emissions and the subsequent secondary aerosol formation was investigated for a Euro 5 flex-fuel gasoline vehicle. The emissions were characterized during the New European Driving Cycle (NEDC) using high time-resolution instruments. The chemical composition of the exhaust particulate matter was studied using a soot particle aerosol mass spectrometer (SP-AMS), and the secondary aerosol formation was studied with an oxidation chamber.