Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

Cui, Min; Chen, Yingjun; Feng, Yanli; Li, Cheng; Zheng, Junyu; Tian, Chongguo; Yan, Caiqing; Zheng, Mei

doi:https://doi.org/10.5194/acp-17-6779-2017

Articles | Volume 17, issue 11

https://doi.org/10.5194/acp-17-6779-2017

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

Special issue:

East Asia emissions assessment (EA2)

https://doi.org/10.5194/acp-17-6779-2017

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

Articles | Volume 17, issue 11

Research article

|

09 Jun 2017

Research article |

| 09 Jun 2017

Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

Min Cui, Yingjun Chen, Yanli Feng, Cheng Li, Junyu Zheng, Chongguo Tian, Caiqing Yan, and Mei Zheng

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Final revised paper (published on 09 Jun 2017)
Supplement to the final revised paper
Preprint (discussion started on 06 Dec 2016)
Supplement to the preprint

Interactive discussion

Status: closed

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

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RC1: 'Comments on manuscript by Cui et al.', Anonymous Referee #1, 25 Dec 2016
- AC1: 'Response to referee 1', Min Cui, 22 Feb 2017
RC2: 'Review of Cui et al.', Anonymous Referee #2, 03 Jan 2017
- AC2: 'Response to referee 2', Min Cui, 22 Feb 2017

Peer-review completion

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

AR by Anna Wenzel on behalf of the Authors (03 Mar 2017) Author's response

ED: Referee Nomination & Report Request started (03 Mar 2017) by Gregory Frost

RR by Anonymous Referee #2 (21 Mar 2017)

RR by Anonymous Referee #1 (27 Mar 2017)

Suggestions for revision or reasons for rejection

The authors have addressed most of my concerns in this revised manuscript. Quality of the presentation and text is much improved, although as mentioned below some proofreading is still needed. I still have other concerns about the dataset and presentation of the results that are highlighted below; therefore, I cannot support publishing the manuscript as is.
My most important comment is related to the sample size and conclusions drawn from the results (#1 below).
1. In response to comment #9 from the 2nd referee, the authors mentioned that "Considering the limit of sample size of our study, it was difficult to calculate the influence of the fuel quality and the emission standards on PM constituents separately."; Yet, in abstract (and p. 12, line 12-13) it is suggested that the lower EF(PM) in stage 2 compared to pre-stage 1 is due to the regulations. A few sentenced lower, it's also mentioned that "Although the EFPM for excavators and trucks was reduced by the constraint of stringent emission standards,...". P11, line 23-24: "The wide range in EFPM values here could be due to the difference in the selection of excavators emission standards"; p13, line 5-8: "As shown in Figure 4 , reductions in the measured EFPM between the China II and China IV trucks and between the China III and China IV trucks were 63.5% and 65.6%, indicating that improvement in the emission standards for diesel trucks could significantly reduce PM emissions." Conclusions: "The average EFPM for excavators with different emission standards decreased by 58% 25 from pre-stage 1 to stage 2" and "Moreover, the reductions in EFPM from the China II to the China IV truck and from the China III to the China IV truck were 63.5 and 65.6%, respectively, Indicating that improvements to the emission standards for diesel trucks and excavators have significantly decreased PM emissions." Consistent with what both referees showed concerns for and the fact that the authors also admitted this shortcoming in their study, I believe the conclusions made in various parts of the paper (as highlighted above) are not valid and need to be rephrased.

2. In response to one of my previous comments (#17) authors mentioned that ambient PM throughout the paper refers to particles smaller than 100 um . Line 4, page 4, I can't imagine that in a country where dust can also contribute significantly to ambient PM, >90% of PM is from diesel vehicles. What size range (and under what conditions) are these statistics applicable to?

3. comment #4: >100% recovery for some species are reported. Were the final numbers adjusted for this recovery rate? (also species that had <100% recovery)?

4. Comment #10: It's unclear why having used a truck for carrying ironstone would lead to higher Fe, Cu, Zn in the exhaust? Your response suggests these species were not coming from the exhaust, but yet the text suggests otherwise. This makes me wonder then if other measurements are also affected by ambient concentrations. The sections on elemental composition and differences are not well supported in my opinion.

5. Comment #11: why not report trace metal EFs for individual excavators? Having the sum for E1+E6 and the rest doesn't make sense.

6. Comment #16: also define BaP(eq) in line 10, page 11

7. Section 3.3 still needs proof-reading

8. Section 3.4: fully write out all the PAHs

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ED: Reconsider after minor revisions (Editor review) (28 Mar 2017) by Gregory Frost

AR by Min Cui on behalf of the Authors (07 Apr 2017) Author's response Manuscript

ED: Reconsider after minor revisions (Editor review) (19 Apr 2017) by Gregory Frost

AR by Min Cui on behalf of the Authors (27 Apr 2017) Author's response Manuscript

ED: Publish as is (28 Apr 2017) by Gregory Frost

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Short summary

PM emitted from diesel vehicles has a severe impact on air quality and human health. However, characteristics of PM from diesel vehicles, particularly measured under real-world condition, are scarce. In this study, 6 excavators and 5 trucks were tested to characterize constituents of PM. PM emission factor (EFPM) and compositions were affected by fuel quality, operating modes and emission standards. Moreover, EFPM and risk of carcinogenic for excavators were 1.7 and 31 fold of those for trucks.