Size-resolved source apportionment of particulate matter in urban Beijing  during haze and non-haze episodes

Tian, S. L.; Pan, Y. P.; Wang, Y. S.

doi:https://doi.org/10.5194/acp-16-1-2016

Articles | Volume 16, issue 1

https://doi.org/10.5194/acp-16-1-2016

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

https://doi.org/10.5194/acp-16-1-2016

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

Articles | Volume 16, issue 1

Research article

|

14 Jan 2016

Research article |

| 14 Jan 2016

Size-resolved source apportionment of particulate matter in urban Beijing during haze and non-haze episodes

S. L. Tian, Y. P. Pan, and Y. S. Wang

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Final revised paper (published on 14 Jan 2016)
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Preprint (discussion started on 30 Mar 2015)
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Interactive discussion

Status: closed

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

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SC C1293: 'Size-resolved source apportionment of particulate matter in urban Beijing during haze and non-haze episodes', Xia Ke, 03 Apr 2015
- AC C5379: 'Response to Xia Ke', Yuepeng Pan, 29 Jul 2015
RC C1994: 'Detail Review', Anonymous Referee #2, 28 Apr 2015
- AC C5380: 'Response to Anonymous Referee #2', Yuepeng Pan, 29 Jul 2015
- AC C5391: 'Response to Anonymous Referee #2 - correct version', Yuepeng Pan, 29 Jul 2015
RC C3767: 'Review', Anonymous Referee #1, 17 Jun 2015
- AC C5388: 'Response to Anonymous Referee #1', Yuepeng Pan, 29 Jul 2015

Peer-review completion

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

AR by Yuepeng Pan on behalf of the Authors (26 Aug 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (23 Sep 2015) by Min Shao

RR by Anonymous Referee #3 (04 Oct 2015)

Suggestions for revision or reasons for rejection

In this manuscript, the authors report on measurements of various chemical species in size-segregated particle samples that were collected over one-year period in the urban area of Beijing. Their results showed that the abundance and chemical compositions of particles varied temporally and spatially, with the major contributions from organics and secondary inorganics. They also showed that the mass fraction of organics decreased but the total mass fraction of sulfate (SO42−), nitrate (NO3−), and ammonium (NH4+) increased from non-haze to haze days. The authors further speculated that heterogeneous reactions and meteorological factors, such as relative humidity and wind speed, might be responsible for haze pollution in Beijing. They concluded that future air pollution control strategies should consider wind patterns and the detailed size-resolved information is needed to characterize the sources of particulate matter (PM) in urban regions. This work represents few studies to investigate the size-resolved source apportionment of PM in Beijing, and their results may have important implications on regulatory control for PM in that country. The article was reasonably written, although the paper would certainly be benefited from additional editing for English usage. I recommend that paper can be published in ACP, provided the following issues have been adequately addressed.

Their results showed that OM dominated in fine particles and decreased from 37.9% on non-haze days to 31.2% on haze days. Such an observation may reflect two distinct processes during haze formation in Beijing. For example, new particle formation has been found to be prevalent in Beijing during clean period (Guo et al., 2014). There is large evidence showing that organics play a key role in new particle formation, both to enhance aerosol nucleation and growth of freshly nucleated particles (Science 304, 1487, 2004; Chem. Rev. 112, 1957, 2012). Such an aspect should be clearly discussed.

In contrast, their results showed that the contribution of SNA to the PM2.1 mass increased from 19.1% on non-haze days to 33.9% on haze days, indicating that SNA played a key role in haze formation. Although the process related to sulfate formation is still inadequately understood at the present time, but the recent literature on such a topic should be clearly discussed. Also, the issues regarding heterogeneous reactions and the effects of RH on aerosol growth need to be further addressed. They may refer the relevant topics discussed in a recent review article (Chem. Rev. 115, 3803, 2015).

Furthermore, the size-resolved variations in particle composition, hygroscopicity, and density (Figs. 3 and 4 in that paper) during haze formation in Beijing have already reported in Guo et al. (2014). Comparisons between that work and the present study should be clearly made.

Suggestions for English improvements

The abstract was too long and should be written in a more concise manner. Perhaps most of the numbers provided could be omitted.

The usage of tenses needs to be consistent. One such an example is given here. “Although OM dominates in fine particles, it decreased from 37.9% on non-haze days to 31.2% on haze days.” (lines 818-819)

There are quite a few acronyms for chemicals throughout the manuscript. Please ensure that those were defined only once at their first usage. For example, OC was defined at least twice (lines 90 and 220).

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RR by Anonymous Referee #2 (05 Oct 2015)

ED: Publish as is (08 Oct 2015) by Min Shao

AR by Yuepeng Pan on behalf of the Authors (18 Oct 2015) Author's response Manuscript

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Short summary

Size-resolved chemical information of particulate matter remains unclear in China due to a paucity of measurement data. One-year observation of water-soluble ions, carbonaceous species and trace elements in size-resolved particles with cutoff points as 0.43, 0.65, 1.1, 2.1, 3.3, 4.7, 5.8 and 9.0 μm were conducted in mega city Beijing. This unique dataset provided multidimensional insights into the sources among different size fractions, seasons or wind flows and between non-haze and haze days.