Chemical characterization of organic particulate matter from on-road traffic in São Paulo, Brazil

Oyama, Beatriz Sayuri; Andrade, Maria de Fátima; Herckes, Pierre; Dusek, Ulrike; Röckmann, Thomas; Holzinger, Rupert

doi:https://doi.org/10.5194/acp-16-14397-2016

Articles | Volume 16, issue 22

https://doi.org/10.5194/acp-16-14397-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/acp-16-14397-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 16, issue 22

Research article

|

18 Nov 2016

Research article |

| 18 Nov 2016

Chemical characterization of organic particulate matter from on-road traffic in São Paulo, Brazil

Beatriz Sayuri Oyama, Maria de Fátima Andrade, Pierre Herckes, Ulrike Dusek, Thomas Röckmann, and Rupert Holzinger

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Final revised paper (published on 18 Nov 2016)
Supplement to the final revised paper
Preprint (discussion started on 01 Dec 2015)
Supplement to the preprint

Interactive discussion

Status: closed

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

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RC C11316: 'Comments on “Vehicular emissions of organic particulate matter in Sao Paulo, Brazil” by Oyama et al.', Anonymous Referee #1, 10 Jan 2016
- AC C13696: 'Answer to referee#1', Beatriz Oyama, 20 Jun 2016
RC C11378: 'Review for “Vehicular emissions of organic particulate matter in Sao Paulo, Brazil” by B.S. Oyama et. al., submitted to Atmospheric Chemistry and Physics.', Anonymous Referee #2, 11 Jan 2016
- AC C13697: 'Answer to referee #2', Beatriz Oyama, 20 Jun 2016

Peer-review completion

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

AR by Beatriz Oyama on behalf of the Authors (07 Jul 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (18 Jul 2016) by Stefania Gilardoni

RR by Anonymous Referee #2 (28 Jul 2016)

Suggestions for revision or reasons for rejection

The authors have addressed most of the prior concerns and thus I find the manuscript acceptable for publication after further minor revisions are addressed. All comments are provided below:

Line 12-13 (abstract): remove “,” after “Both” and “emissions”
Line 35-36 (abstract): The authors say that “chemical processing close to the engine/tailpipe region is an important control on primary organic aerosol emission.” Usage of the term “control” is a bit ambiguous. I’m not sure what exactly the authors are trying to express. Please clarify the sentence.
Line 42: Change “shortly referred to as diesel afterwards” to “henceforth referred to as diesel”
Line 43: Add space after “(E100)”
Line 52: Add a “.” After “E100”
Line 69-70: With regards to findings of Salvo and Geiger, it’s not clear to me what you’re trying to say. Is it a lab study? Did they replace gasoline with ethanol? Or are you saying that they found an overall decrease in ozone and they speculate this was due to replacing gasoline with ethanol? Please clarify.
Line 78: Change “only little effect” to “a moderate effect”. You can substitute “moderate” with “insignificant” or whatever you find appropriate based on the citation.
Line 79: Change “amount” to “amounts”
Line 80: add “a” before “significant”
Line 83: change “on” to “of”
Line 101: change “`” to “’”
Line 104: change “presenting” to “linked to” or “associated with”
Line 106: remove “in”
Line 124: add “has” after “far”
Line 139 and 144: no need to redefine LDV and HDV since they are defined in introduction.
Line 214: change “focused” to “focus”
Line 276: remove “just”
Line 278: In line 122 you stated that Perez-Martinez found LDV emitted more CO than HDV. That contradicts what you have stated here. Is there a reason the study mentioned earlier has different findings than the studies you cited in lines 278-279?
Line 305: add “of” after “type”, change “no significant” to “an insignificant”
Line 340: change “OC .Zhang” to “OC. Zhang”
Line 364: add “is” after “peak”
Line 365: change “on” to “at”
Lines 371-374: Was this ion seen in PM10 filter results? I believe this whole study is only for PM2.5 but in your methods you state that PM10 particles were collected.
Line 389: again, the use of the word “control” is misleading. Maybe you mean that it’s an important factor. But this begs the question of what you mean by “chemical processing close to the engine/tailpipe region”. I’m not sure if you mean the actual combustion process or that somehow emissions are becoming oxidized at the tailpipe. This statement is extremely vague and should be clarified. Try to find an appropriate citation from another study that discusses the mechanism that converts fuel to a more oxidized emission.
Line 392: apply subscript to "x" in “NOx”
Lines 419-429: Did you try recalculating H:C vs O:C after performing a background subtraction in a similar fashion as you did for total OC using the ΔCO method? I would still expect that this type of subtraction could be done in order to remove influence from background components and hence determine the chemistry of the vehicle emissions without external influences.
Line 460: remove “the” after “was”
Line 464: add a space after (2011)
Line 466: remove “,” after “both”
Line 484: change “fuels” to “unburned fuels”
Line 487: change “EF’s” to “EFs”
Tables: In general, I would keep the number of significant figures consistent. Sometimes you use 3 and sometimes you use 4 significant figures. I would stick to at most 3, except for the m/z values which would require higher significant figures.
Figure 4: y-axis should read “Emission Factor”
Figure 6: y-axis should read “Emission Factor”
Supplementary
I would suggest adding a cover page with the phrase “Supplementary information for” and then follow that by the title, author list, affiliations, etc as you have provided at the beginning of the manuscript.

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RR by Anonymous Referee #1 (02 Aug 2016)

ED: Reconsider after major revisions (03 Aug 2016) by Stefania Gilardoni

AR by Beatriz Oyama on behalf of the Authors (27 Sep 2016) Author's response

ED: Publish subject to technical corrections (04 Oct 2016) by Stefania Gilardoni

AR by Beatriz Oyama on behalf of the Authors (11 Oct 2016) Manuscript

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Short summary

Vehicular emissions have a strong impact on air pollution in big cities; hence, the study was performed in São Paulo city, where light- (LDVs) and heavy-duty vehicles (HDVs) run on different fuels. We find that organic aerosol emission from LDVs and HDVs is a complex process involving oxidation of fuel constituents, NO_x chemistry, and condensation of unburned fuel hydrocarbons on new or existing particles. The obtained emission patterns can be used to study processing of young aerosol in Brazil.