Long-term historical trends in air pollutant emissions in Asia: Regional Emission inventory in ASia (REAS) version 3

Kurokawa, Junichi; Ohara, Toshimasa

doi:https://doi.org/10.5194/acp-20-12761-2020

Articles | Volume 20, issue 21

https://doi.org/10.5194/acp-20-12761-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-20-12761-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 20, issue 21

Research article

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04 Nov 2020

Research article | Highlight paper |

| 04 Nov 2020

Long-term historical trends in air pollutant emissions in Asia: Regional Emission inventory in ASia (REAS) version 3

Junichi Kurokawa and Toshimasa Ohara

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Final revised paper (published on 04 Nov 2020)
Supplement to the final revised paper
Preprint (discussion started on 20 Dec 2019)
Supplement to the preprint

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Referee comments on Long-term historical trends in air pollutant emissions in Asia', Anonymous Referee #1, 26 Jan 2020
- AC1: 'Response to Comments by Anonymous Referee #1', Jun-ich Kurokawa, 09 Aug 2020
RC2: 'Comments on REAS v3.1 paper', Anonymous Referee #2, 16 Feb 2020
- AC2: 'Response to Comments by Anonymous Referee #2', Jun-ich Kurokawa, 09 Aug 2020

Peer-review completion

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

AR by Jun-ich Kurokawa on behalf of the Authors (10 Aug 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (15 Aug 2020) by Qiang Zhang

RR by Anonymous Referee #1 (22 Aug 2020)

Suggestions for revision or reasons for rejection

I've reviewed the revised paper "Long-term historical trends in air pollutant emissions in Asia: Regional Emission inventory in ASia (REAS) version 3" by Kurokawa and Ohara. The authors have done an excellent job responding to the review comments and describing the assumptions and methods used in this work.

Line 10: "The average total emissions in Asia during 1950-1955 and from 2010-2015 (growth rates in these 60 years)"

1950 - 2015 is 65 years?
(I see now on line 470 this is defined. Define this on first use of the 60-year period in the main text or, better yet, in the first paragraph of section "3.1 Trends of Asian and national emissions".)

Line 452
"which were relatively large even in past years in Asia."
did the authors perhaps mean to say "even in recent Asia"?
(Otherwise I'm not quite sure what this means. In earlier times residential emissions dominate over other sectors in general before widespread industrialization)

It would be useful to get the author's perspective in section "3.4 Uncertainty" on uncertainty in emission trends given their extensive work with emissions data for this region. I realize this was not qualitatively estimated, but at least a qualitative discussion would be useful. In particular, as the author's noted in their response to reviewer comments, detailed information on emission control (and technology changes) were not available for all regions. So for some regions one would presume that recent trends might be more uncertain as a result due to lack of information. Similarly, for SO2, as mentioned in the current text, sulfur content in fuels is not known for the entire time period, which could impact trends.

Comments on Supplement: Kurokawa_and_Ohara_Supplement_Methodology

Page 36, Section on SO2 Emission Factors
It is not clear what the units are here. Are these the fraction of Sulfur in the fuel that is emitted as SO2? Please clarify.

Page 37 and forward, "Settings of emission controls".

In the China section, please clarify if "In 2015, reduction rates of SO2 emissions were assumed to be 75%, 63%, and 52% for (A), (B), and (C), respectively."

It is not clear if this is the assumed reduction per FGD unit, the total reduction as a result of the FGD deployment, or some other percentage (FGD penetration in 2015? Although this seems low.). Please clarify.

Throughout this section, where not otherwise noted (it is in some places), please indicate what the assumed reduction fraction for FGD units are (since penetration rates are already given in general).

Page 51 "Settings of emission controls" for primary particulate emissions.

Please clarify how these assumptions impact BC/OC. Were the PM2.5 reduction assumptions applied to BC and OC, or were some other assumptions used?

Page 55

It appears that CO2 emissions are a mix of fossil CO2 emissions and short-cycle CO2 emissions (e.g. from biomass sources, etc.). If so please make sure in the data release that these are reported separately.

On page 142 it says: "(Note that uncertainties for SO2 here were only for ratios of sulfur in fuels emitted as SO2 and influences of uncertainties in sulfur contents in fuels were not included.)"

While on page 143 it says "For SO2, in addition to uncertainties for ratios of sulfur emitted as SO2, those in sulfur contents in fuels need to be taken into considered. "

This was a bit confusing. Please clarify.

Table 10.3. Settings of uncertainties of removal efficiencies

For removal efficiencies it would be useful to clarify how these uncertainties were applied. Given that this is used in an emission factor calculation as (1 - removal-efficiency), a multiplicative uncertainty could result in a removal efficiency larger than 1, but I assume something else was done (or max efficiency capped?).

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RR by Anonymous Referee #2 (28 Aug 2020)

ED: Publish subject to minor revisions (review by editor) (01 Sep 2020) by Qiang Zhang

AR by Jun-ich Kurokawa on behalf of the Authors (06 Sep 2020) Author's response Manuscript

ED: Publish as is (13 Sep 2020) by Qiang Zhang

AR by Jun-ich Kurokawa on behalf of the Authors (21 Sep 2020) Author's response Manuscript

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Short summary

A long historical emission inventory of major air pollutants in Asia during 1950–2015 was developed as Regional Emission inventory in ASia version 3 (REASv3). Trends of emissions and changes in source contributions in countries and regions in Asia during these 6 decades were analyzed. REASv3 provides monthly gridded data with 0.25° by 0.25° resolution for major source categories as well as table of emissions by countries and sub-regions for major sectors and fuel types.