气候变化领域集成服务门户(CCPortal): Response of particle number concentrations to the clean air action plan: Lessons from the first long-term aerosol measurements in a typical urban valley in western China

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DOI	10.5194/acp-21-14959-2021
	Response of particle number concentrations to the clean air action plan: Lessons from the first long-term aerosol measurements in a typical urban valley in western China
	Zhao S.; Yu Y.; Li J.; Yin D.; Qi S.; Qin D.
发表日期	2021
ISSN	1680-7316
起始页码	14959
结束页码	14981
卷号	21 期号:19
英文摘要	The strictest ever clean air action (CAA) plan has been implemented by the Chinese government since 2013 to alleviate the severe haze pollution. The PM2.5 mass concentration was found to largely be reduced in response to emission mitigation policies, but the response of particle number concentrations (PNCs) to CAA was less evaluated in the previous studies, which may be significantly different from PM2.5 mass due to newly formed particle impacts. In this work, the first in situ observation of particle number size distributions (PNSDs) during 2012-2019 in urban Lanzhou was used to analyze long-term PNC variations and CAA impacts. The average number of particles in nucleation (N13-25, particle number in the size range of 13-25nm), Aitken (N25-100, particle number in the size range of 25-100nm) and accumulation (N100-800, particle number in the size range of 100-800nm) modes were respectively 2514.0, 10768.7 and 3258.4cm-3, and N25-100 accounted for about 65.1% of total PNCs during the campaign. The k-means clustering technique was used to classify the hourly mean PNSDs into six clusters, and each cluster corresponded to a specific source and influencing factor. The polluted clusters governed the winter PNCs before 2016, and their occurrence was less and less frequent after 2016, which was largely dominated by reduction in primary emissions. However, the contribution of new particle formation (NPF) events to summer N13-25 decreased from 50% to about 10% during 2013 to 2015 and then increased to reach around 60% in 2019. The trends of size-resolved PNCs for each cluster were quantified by Theil-Sen regression. The size-segregated PNCs exhibited downward trends for all clusters during 2012-2015, especially in spring. The annual relative slopes of spring PNCs varied from -54.7% to -17.2%, -42.6% to -14.1%, and -40.7% to -17.5% per year for 13-25, 25-100, and 100-800nm size ranges, and the reduction in the polluted clusters was much larger than NPF clusters. The ultrafine particle number was increased, and the amplitude was much greater during 2016-2019. The annual relative slopes of N13-25 varied between 8.0% in fall and 135.5% in spring for the NPF cluster. In response to CAA, the increased daytime net radiation, higher ambient temperature and lower relative humidity at noon for NPF events also could partly explain the higher N13-25 induced by the more frequent nucleation events after 2016, especially in spring. The air masses were mainly from the adjacent regions of urban Lanzhou and less affected by long-range transport for NPF events, and thus the particles were not easily grown by coagulation during transport processes, which was helpful for the occurrence of NPF events. Therefore, some effective measures to cooperatively control particle number concentration and mass should be taken for the Chinese megacities. © Copyright:
语种	英语
scopus关键词	action plan; aerosol; concentration (composition); emission control; governance approach; haze; long range transport; megacity; particle size; pollutant transport; pollution monitoring; urban atmosphere; China
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
来源机构	中国科学院西北生态环境资源研究院
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246522
作者单位	Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Pingliang Land Surface Process and Severe Weather Research Station, Pingliang, 744015, China; Gansu Land Surface Process and Severe Weather Observation and Research Station, Pingliang, 744015, China; State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Beijing, 100049, China
推荐引用方式 GB/T 7714	Zhao S.,Yu Y.,Li J.,et al. Response of particle number concentrations to the clean air action plan: Lessons from the first long-term aerosol measurements in a typical urban valley in western China[J]. 中国科学院西北生态环境资源研究院,2021,21(19).
APA	Zhao S.,Yu Y.,Li J.,Yin D.,Qi S.,&Qin D..(2021).Response of particle number concentrations to the clean air action plan: Lessons from the first long-term aerosol measurements in a typical urban valley in western China.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(19).
MLA	Zhao S.,et al."Response of particle number concentrations to the clean air action plan: Lessons from the first long-term aerosol measurements in a typical urban valley in western China".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.19(2021).