Exploring the nonlinear relationship between air pollution and precursor emissions in Qingdao, eastern China is crucial for improving air quality. We simulated 32 emission reduction scenarios based on different volatile organic compound (VOC) and nitrogen oxide (NOx) emission reduction ratios using the Weather Research and Forecasting-Comprehensive Air Quality Model Extensions model. The emission reduction of VOCs was beneficial for reducing fine particulate matter (PM2.5) concentration in January and ozone (O3) concentration in June. However, NOx must be reduced by at least 48% and 70% to decrease PM2.5 and O3 concentrations, respectively, when VOCs are not reduced. The responses of PM2.5 and O3 concentrations to emission reductions from different sources were also evaluated. The reduction in VOC emissions from different sources decreased the PM2.5 concentration in January, and O3 concertation in June, while NOx reduction resulted in an increase. Controlling VOC emissions from industry has a positive effect on improving local PM2.5 and O3, while the emission reductions of NOx from transportation and industry are not conducive to reducing PM2.5 and O3 concentrations. The synergistic emission reduction pathways for NOx and VOCs during PM2.5 and O3 combined pollution were also analyzed. The VOC and NOx emission reductions were beneficial for reducing the comprehensive Air Quality Index (sAQI) values. When the NOx emission reduction was large, the sAQI improvement gradually exceeded that of VOCs. A collaborative optimization path should be adopted that focuses on controlling VOCs first, and further control of combined pollution should depend on the deep reduction of NOx.
Emissions without VOCs or NOx from power, industry, residential, and transportation, respectively
Tab.1
Fig.1
Fig.2
Fig.3
Fig.4
Fig.5
1
L Chen, J Zhu, H Liao, Y Yang, X Yue. (2020). Meteorological influences on PM2.5 and O3 trends and associated health burden since China’s clean air actions. Science of the Total Environment, 744: 140837 https://doi.org/10.1016/j.scitotenv.2020.140837
2
D Ding, J Xing, S Wang, Z Dong, F Zhang, S Liu, J Hao. (2022). Optimization of a NOx and VOC cooperative control strategy based on clean air benefits. Environmental Science & Technology, 56(2): 739–749 https://doi.org/10.1021/acs.est.1c04201
3
Z Dong, D Ding, Y Jiang, H Zheng, J Xing, S Wang (2023a). Responses of PM2.5 and O3 to emission reduction and meteorology variation and their policy implications. Research of Environmental Sciences, 36: 223–236 (in Chinese)
4
Z Dong, J Xing, F Zhang, S Wang, D Ding, H Wang, C Huang, H Zheng, Y Jiang, J Hao. (2023b). Synergetic PM2.5 and O3 control strategy for the Yangtze River Delta, China. Journal of Environmental Sciences, 123: 281–291 https://doi.org/10.1016/j.jes.2022.04.008
5
T Fang, Y Zhu, S Wang, J Xing, B Zhao, S Fan, M Li, W Yang, Y Chen, R Huang. (2021). Source impact and contribution analysis of ambient ozone using multi-modeling approaches over the Pearl River Delta region, China. Environmental Pollution, 289: 117860 https://doi.org/10.1016/j.envpol.2021.117860
6
T Feng, S Zhao, N Bei, J Wu, S Liu, X Li, L Liu, Y Qian, Q Yang, Y Wang. et al.. (2019). Secondary organic aerosol enhanced by increasing atmospheric oxidizing capacity in Beijing–Tianjin–Hebei (BTH), China. Atmospheric Chemistry and Physics, 19(11): 7429–7443 https://doi.org/10.5194/acp-19-7429-2019
7
L Hui, T Ma, Z Gao, J Gao, Z Wang, L Xue, H Liu, J Liu. (2021). Characteristics and sources of volatile organic compounds during high ozone episodes: a case study at a site in the eastern Guanzhong Plain, China. Chemosphere, 265: 129072 https://doi.org/10.1016/j.chemosphere.2020.129072
8
Y Jiang, S Wang, J Xing, B Zhao, S Li, X Chang, S Zhang, Z Dong. (2022). Ambient fine particulate matter and ozone pollution in China: synergy in anthropogenic emissions and atmospheric processes. Environmental Research Letters, 17(12): 123001 https://doi.org/10.1088/1748-9326/aca16a
9
L Kong, M Song, X Li, Y Liu, S Lu, L Zeng, Y Zhang. (2024). Analysis of China’s PM2.5 and ozone coordinated control strategy based on the observation data from 2015 to 2020. Journal of Environmental Sciences, 138: 385–394 https://doi.org/10.1016/j.jes.2023.03.030
10
C Li, S Chen, P Ge, X Ye, Y Zhao (2020). Complex pollution characteristics and source analysis of atmospheric PM2.5 and ozone in Changzhou. Environmental Science and Management, 45: 138–143 (in Chinese)
11
L Li, J Li, M Qin, X Xie, J Hu, Y Zhang. (2024). Variations in summertime ozone in Nanjing between 2015 and 2020: roles of meteorology, radical chain length and ozone production efficiency. Frontiers of Environmental Science & Engineering, 18(11): 137 https://doi.org/10.1007/s11783-024-1897-z
12
P Li, C Chen, D Liu, J Lian, W Li, C Fan, L Yan, Y Gao, M Wang, H Liu. et al.. (2024). Characteristics and source apportionment of ambient volatile organic compounds and ozone generation sensitivity in urban Jiaozuo, China. Journal of Environmental Sciences, 138: 607–625 https://doi.org/10.1016/j.jes.2023.04.016
13
P Liang, T Zhu, Y Fang, Y Li, Y Han, Y Wu, M Hu, J Wang. (2017). The role of meteorological conditions and pollution control strategies in reducing air pollution in Beijing during APEC 2014 and Victory Parade 2015. Atmospheric Chemistry and Physics, 17(22): 13921–13940 https://doi.org/10.5194/acp-17-13921-2017
14
C Lin, P Louie, A Lau, J Fung, Z Yuan, M Tao, X Zhang, M Hossain, C Li, X Lao. (2024). Net effect of air pollution controls on health risk in the Beijing–Tianjin–Hebei region during the 2022 winter Olympics and Paralympics. Journal of Environmental Sciences, 135: 560–569 https://doi.org/10.1016/j.jes.2022.10.008
15
T Liu, Y Hong, M Li, L Xu, J Chen, Y Bian, C Yang, Y Dan, Y Zhang, L Xue. et al.. (2022). Atmospheric oxidation capacity and ozone pollution mechanism in a coastal city of southeastern China: analysis of a typical photochemical episode by an observation-based model. Atmospheric Chemistry and Physics, 22(3): 2173–2190 https://doi.org/10.5194/acp-22-2173-2022
16
X Liu, G Yi, X Zhou, T Zhang, X Bie, J Li, H Tan. (2023a). Spatio-temporal variations of PM2.5 and O3 in China during 2013–2021: impact factor analysis. Environmental Pollution, 334: 122189 https://doi.org/10.1016/j.envpol.2023.122189
17
Y Liu, G Geng, J Cheng, Y Liu, Q Xiao, L Liu, Q Shi, D Tong, K He, Q Zhang. (2023b). Drivers of increasing ozone during the two phases of clean air actions in China 2013−2020. Environmental Science & Technology, 57(24): 8954–8964 https://doi.org/10.1021/acs.est.3c00054
18
Z Liu, Y Wang, B Hu, K Lu, G Tang, D Ji, X Yang, W Gao, Y Xie, J Liu. et al.. (2021). Elucidating the quantitative characterization of atmospheric oxidation capacity in Beijing, China. Science of the Total Environment, 771: 145306 https://doi.org/10.1016/j.scitotenv.2021.145306
19
K Lu, S Guo, Z Tan, H Wang, D Shang, Y Liu, X Li, Z Wu, M Hu, Y Zhang. (2019). Exploring atmospheric free-radical chemistry in China: the self-cleansing capacity and the formation of secondary air pollution. National Science Review, 6(3): 579–594 https://doi.org/10.1093/nsr/nwy073
20
MEE (20162016. Technical Regulation on Ambient Air Quality Index (on trial). Beijing: Ministry of Ecology and Environment of the People’s Republic of China (in Chinese)
21
MEE (2023). Bulletin of China’s Ecological Environment in 2022. Beijing: Ministry of Ecology and Environment of the People’s Republic of China (in Chinese)
22
M Qin, A Hu, J Mao, X Li, L Sheng, J Sun, J Li, X Wang, Y Zhang, J Hu. (2022). PM2.5 and O3 relationships affected by the atmospheric oxidizing capacity in the Yangtze River Delta, China. Science of the Total Environment, 810: 152268 https://doi.org/10.1016/j.scitotenv.2021.152268
23
QMBS (20232023. Qingdao Statistical Yearbook of 2023. Qingdao: Qingdao Municipal Bureau of Statistics (in Chinese)
24
SPBS (20222022. Shandong Statistical Yearbook of 2022. Jinan: Shandong Provincial Bureau of Statistics (in Chinese)
25
J Shen, Q Zhao, Z Cheng, P Wang, Q Ying, J Liu, Y Duan, Q Fu. (2020). Insights into source origins and formation mechanisms of nitrate during winter haze episodes in the Yangtze River Delta. Science of the Total Environment, 741: 140187 https://doi.org/10.1016/j.scitotenv.2020.140187
26
L Shu, T Wang, M Xie, M Li, M Zhao, M Zhang, X Zhao. (2019). Episode study of fine particle and ozone during the CAPUM-YRD over Yangtze River Delta of China: characteristics and source attribution. Atmospheric Environment, 203: 87–101 https://doi.org/10.1016/j.atmosenv.2019.01.044
27
B Wang, Y Tang, Y Liu, H Wu, X Li, Y Li (2021). Mechanism of complex pollution of O3 and PM2.5 in Yangtze River Delta region. Environmental Protection Science,47: 38–38 (in Chinese)
28
G Wang, Z Zhu, Z Liu, X Liu, F Kong, L Nie, W Gao, N Zhao, J Lang. (2022a). Ozone pollution in the plate and logistics capital of China: insight into the formation, source apportionment, and regional transport. Environmental Pollution, 313: 120144 https://doi.org/10.1016/j.envpol.2022.120144
29
J Wang, A Gao, S Li, Y Liu, W Zhao, P Wang, H Zhang. (2023). Regional joint PM2.5-O3 control policy benefits further air quality improvement and human health protection in Beijing-Tianjin-Hebei and its surrounding areas. Journal of Environmental Sciences, 130: 75–84 https://doi.org/10.1016/j.jes.2022.06.036
30
J Wang, C Liu (2022). Study on the synergistic control of PM2.5 and O3 pollution in the Yangtze River Delta region based on WRF-Chem model. Acta Scientiae Circumstantiae, 42: 32–42 (in Chinese)
31
L Wang, M Li, Q Wang, Y Li, J Xin, X Tang, W Du, T Song, T Li, Y Sun. et al.. (2022b). Air stagnation in China: spatiotemporal variability and differing impact on PM2.5 and O3 during 2013–2018. Science of the Total Environment, 819: 152778 https://doi.org/10.1016/j.scitotenv.2021.152778
32
Y Wang, Z Liu, L Huang, G Lu, Y Gong, E Yaluk, H Li, X Yi, L Yang, J Feng. et al.. (2020). Development and evaluation of a scheme system of joint prevention and control of PM2.5 pollution in the Yangtze River Delta region, China. Journal of Cleaner Production, 275: 122756 https://doi.org/10.1016/j.jclepro.2020.122756
33
Y Wang, W Song, W Yang, X Sun, Y Tong, X Wang, C Liu, Z Bai, X Liu. (2019). Influences of atmospheric pollution on the contributions of major oxidation pathways to PM2.5 nitrate formation in Beijing. Journal of Geophysical Research. Atmospheres, 124(7): 4174–4185 https://doi.org/10.1029/2019JD030284
34
W Wei, X Wang, X Wang, R Li, C Zhou, S Cheng. (2022). Attenuated sensitivity of ozone to precursors in Beijing–Tianjin–Hebei region with the continuous NOx reduction within 2014–2018. Science of the Total Environment, 813: 152589 https://doi.org/10.1016/j.scitotenv.2021.152589
35
S Xiang, J Liu, W Tao, K Yi, J Xu, X Hu, H Liu, Y Wang, Y Zhang, H Yang. et al.. (2020). Control of both PM2.5 and O3 in Beijing-Tianjin-Hebei and the surrounding areas. Atmospheric Environment, 224: 117259 https://doi.org/10.1016/j.atmosenv.2020.117259
36
Q Xiao, G Geng, T Xue, S Liu, C Cai, K He, Q Zhang. (2022). Tracking PM2.5 and O3 pollution and the related health burden in China 2013−2020. Environmental Science & Technology, 56(11): 6922–6932 https://doi.org/10.1021/acs.est.1c04548
37
Y Xie, L Zhao, J Xue, H Gao, H Li, R Jiang, X Qiu, S Zhang. (2018). Methods for defining the scopes and priorities for joint prevention and control of air pollution regions based on data-mining technologies. Journal of Cleaner Production, 185: 912–921 https://doi.org/10.1016/j.jclepro.2018.03.101
38
L Xing, X Mao, K Duan. (2022). Impacts of urban–rural disparities in the trends of PM2.5 and ozone levels in China during 2013–2019. Atmospheric Pollution Research, 13(11): 101590 https://doi.org/10.1016/j.apr.2022.101590
39
J Xue, F Wang, K Zhang, H Zhai, D Jin, Y Duan, E Yaluk, Y Wang, L Huang, Y Li. et al.. (2023). Elucidate long-term changes of ozone in Shanghai based on an integrated machine learning method. Frontiers of Environmental Science & Engineering, 17(11): 138 https://doi.org/10.1007/s11783-023-1738-5
40
W Yang, J Li, Z Wang, L Wang, X Dao, L Zhu, X Pan, Y Li, Y Sun, S Ma. et al.. (2021). Source apportionment of PM2.5 in the most polluted Central Plains Economic Region in China: implications for joint prevention and control of atmospheric pollution. Journal of Cleaner Production, 283: 124557 https://doi.org/10.1016/j.jclepro.2020.124557
41
G Zhang, H Xu, H Wang, L Xue, J He, W Xu, B Qi, R Du, C Liu, Z Li. et al.. (2020). Exploring the inconsistent variations in atmospheric primary and secondary pollutants during the 2016 G20 summit in Hangzhou, China: implications from observations and models. Atmospheric Chemistry and Physics, 20(9): 5391–5403 https://doi.org/10.5194/acp-20-5391-2020
42
Q Zhang, Y Pan, Y He, W Walters, Q Ni, X Liu, G Xu, J Shao, C Jiang. (2021). Substantial nitrogen oxides emission reduction from China due to COVID-19 and its impact on surface ozone and aerosol pollution. Science of the Total Environment, 753: 142238 https://doi.org/10.1016/j.scitotenv.2020.142238
43
S Zhang, H Zheng, J Liu, Y Shi, T Chen, C Xue, F Zhang, Y Jiang, X Zhang, S Sahu. et al.. (2024). Underestimated benefits of NOx control in reducing SNA and O3 based on missing heterogeneous HONO sources. Frontiers of Environmental Science & Engineering, 18(3): 30 https://doi.org/10.1007/s11783-024-1790-y
44
X Zhang, X Xiao, F Wang, G Brasseur, S Chen, J Wang, M Gao. (2022). Observed sensitivities of PM2.5 and O3 extremes to meteorological conditions in China and implications for the future. Environment International, 168: 107428 https://doi.org/10.1016/j.envint.2022.107428
45
Y Zhang, J Dai, Q Li, T Chen, J Mu, G Brasseur, T Wang, L Xue. (2023). Biogenic volatile organic compounds enhance ozone production and complicate control efforts: insights from long-term observations in Hong Kong. Atmospheric Environment, 309: 119917 https://doi.org/10.1016/j.atmosenv.2023.119917
46
N Zhao, G Wang, G Li, J Lang, H Zhang. (2020). Air pollution episodes during the COVID-19 outbreak in the Beijing-Tianjin-Hebei region of China: an insight into the transport pathways and source distribution. Environmental Pollution, 267: 115617 https://doi.org/10.1016/j.envpol.2020.115617
47
X Zhao, G Wang, S Wang, N Zhao, M Zhang, W Yue. (2021). Impacts of COVID-19 on air quality in mid-eastern China: an insight into meteorology and emissions. Atmospheric Environment, 266: 118750 https://doi.org/10.1016/j.atmosenv.2021.118750
48
X Zhao, Z Zhang, J Xu, J Gao, S Cheng, X Zhao, X Xia, B Hu. (2023). Impacts of aerosol direct effects on PM2.5 and O3 respond to the reductions of different primary emissions in Beijing–Tianjin–Hebei and surrounding area. Atmospheric Environment, 309: 119948 https://doi.org/10.1016/j.atmosenv.2023.119948
49
H Zhong, R Huang, Y Chang, J Duan, C Lin, Y Chen. (2021). Enhanced formation of secondary organic aerosol from photochemical oxidation during the COVID-19 lockdown in a background site in Northwest China. Science of the Total Environment, 778: 144947 https://doi.org/10.1016/j.scitotenv.2021.144947
