the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Changes of air pollutant emissions in China during two clean air action periods derived from the newly developed Inversed Emission Inventory for Chinese Air Quality (CAQIEI)
Abstract. A new long-term emission inventory called the Inversed Emission Inventory for Chinese Air Quality (CAQIEI) was developed in this study by assimilating surface observations from the China National Environmental Monitoring Centre (CNEMC) using the ensemble Kalman filter (EnKF) and the Nested Air Quality Prediction Modeling System (NAQPMS). This inventory contains the constrained monthly emissions of NOx, SO2, CO, primary PM2.5, primary PM10, and NMVOCs in China from 2013 to 2020, with a horizontal resolution of 15 km∗15 km. This paper documents detailed descriptions of the assimilation system and the evaluation results for the emission inventory. The results suggest that CAQIEI can effectively reduce the biases in the a priori emission inventory, with the normalized mean biases ranging from −9.1 % to 9.5 % in the a posteriori simulation, which are significantly reduced from the biases in the a priori simulations (−45.6 % to 93.8 %). The calculated RMSEs (0.3 mg/m3 for CO and 9.4–21.1 μg/m3 for other species, on the monthly scale) and correlation coefficients (0.76–0.94) were also improved from the a priori simulations, suggesting that CAQIEI can reasonably reproduce the magnitude and variation of emissions of different air pollutants in China. Based on CAQIEI, we estimated China’s total emissions (including both natural and anthropogenic emissions) of the 6 species in 2015 to be as follows: 25.2 Tg of NOx, 17.8 Tg of SO2, 465.4 Tg of CO, 15.0 Tg of PM2.5, 40.1 Tg of PM10, and 46.0 Tg of NMVOCs. From 2015 to 2020, the total emissions reduced by 54.1 % for SO2, 44.4 % for PM2.5, 33.6 % for PM10, 35.7 % for CO, and 15.1 % for NOx, but increased by 21.0 % for NMVOCs. Larger emission reductions were achieved during the 2018–2020 action plan than during the 2013–2017 action plan for most species. In particular, NOx and NMVOC emissions were shown to increase during the 2013–2017 action plain, and there were obvious emission increases in the Fengwei Plain area over the Central China region. However, NOx and NMVOC emissions declined during the 2018–2020 action plan, and the emissions over the Fengwei Plain area also decreased. This suggests that the emission control policies were improved in the 2018–2020 action plan. We also compared CAQIEI with previous inventories, which verified our inversion results in terms of total emissions of NOx, SO2 and NMVOCs, and more importantly identified the potential uncertainties in our current understanding of China’s air pollutant emissions. Firstly, CO emissions in China may be substantially underestimated by current inventories, with the CO emissions estimated by CAQIEI (426.8 Tg) being more than twice the amount in previous inventories (120.7–237.7 Tg). Significant underestimations for other air pollutant emissions may also exist over western and northeastern China. In addition, the NMVOC emissions were shown to be substantially underestimated over northern China but overestimated in southern China. Secondly, the emission reduction rates during 2015–2018 estimated by CAQIEI are generally smaller than those estimated by previous inventories, especially for NOx, PM10 and NMVOCs, suggesting that the mitigation effects of the air pollution control may be overestimated currently. In particular, China’s NMVOC emissions were shown to have increased by 26.6 % from 2015 to 2018, especially over the North China Plain (by 38.0 %), Northeast China (by 38.3 %), and Central China (60.0 %). In contrast, the emissions reduction rate of CO may be underestimated. Overall, our emissions inventory sheds new light on the complex variations of air pollutant emissions in China during its two recent clean air action periods, which could significantly improve our understanding of air pollutant emissions and related changes in air quality in China. The datasets are available at https://doi.org/10.57760/sciencedb.13151 (Kong et al., 2023).
- Preprint
(3255 KB) - Metadata XML
-
Supplement
(1194 KB) - BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on essd-2023-477', Anonymous Referee #1, 01 Feb 2024
This is a valuable high-resolution emission dataset for China, and the paper is well-structured.
However, I have some questions and suggestions:
-
In Figure 4, compared to other pollutants, NOx and VOC emissions still show distributions in the Tibet region of China . Could you provide more information about the sources of NOx and VOC in this region?
-
Could you display the temporal trends in emissions from 2013 to 2020 for China and its sub-regions, comparing different inventories (multiple lines) to better illustrate the changes in emission patterns over time?
-
As a high-resolution grid product, is it possible to include a comparison at the grid scale with other inventories?
-
In Figure 12, the profiles presented in this study differ from previous research, especially for SO2 and PM10. Are the monthly simulation results for SO2 and PM10 superior to the simulation results using other inventories?
Additionally, it would be interesting to see further validation results from more models (e.g., WRF-CMAQ) using this dataset as input in the future.
Citation: https://doi.org/10.5194/essd-2023-477-RC1 - AC1: 'Reply on RC1', Lei Kong, 10 Mar 2024
-
-
RC2: 'Comment on essd-2023-477', Anonymous Referee #2, 02 Feb 2024
The comment was uploaded in the form of a supplement: https://essd.copernicus.org/preprints/essd-2023-477/essd-2023-477-RC2-supplement.pdf
- AC2: 'Reply on RC2', Lei Kong, 10 Mar 2024
Data sets
Inversed Emission Inventory for Chinese Air Quality (CAQIEI) version 1.0 Lei Kong, Xiao Tang, Zifa Wang, Jiang Zhu, Jianjun Li, Huangjian Wu, Qizhong Wu, Huansheng Chen, Lili Zhu, Wei Wang, Bing Liu, Qian Wang, Duohong Chen, Yuepeng Pan, Jie Li, Lin Wu, Gregory R. Carmichael https://doi.org/10.57760/sciencedb.13151
Viewed
HTML | XML | Total | Supplement | BibTeX | EndNote | |
---|---|---|---|---|---|---|
355 | 72 | 31 | 458 | 28 | 20 | 21 |
- HTML: 355
- PDF: 72
- XML: 31
- Total: 458
- Supplement: 28
- BibTeX: 20
- EndNote: 21
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1