[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-150431-en":3,"doc-seo-150431-105":30,"detail-sidebar-cat-0-en-105":92},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":27,"seo_description":14,"update_tm":28,"read_time":29},150431,1099513958607,"Jiven","https://ap-avatar.wpscdn.com/avatar/100002390cf8733938c?x-image-process=image/resize,m_fixed,w_180,h_180&k=1778829742770036399",8,"Research & Report","Contribution of Regional PM 2.5 Transport to Air Pollution Enhanced by Sub-Basin Topography - A Modeling Case over Central China","The Twain-Hu basin (THB) in central China has faced severe PM2.5 pollution, while the role of sub-basin topography in shaping air quality remains insufficiently understood. During a heavy PM2.5 episode from 4–10 January 2019, observations and WRF-Chem simulations with sensitivity experiments were used to identify mechanisms. Results show stronger western urban pollution (189.8 µg m−3 vs 106.3 µg m−3) and an overall inverse contribution of terrain effects through regional transport enhancement and boundary-layer ventilation changes.","atmosphere  \nArticle  \nContribution of Regional PM 2.5 Transport to Air Pollution Enhanced by Sub-Basin Topography: A Modeling Case over Central China  \nWeiyang Hu 1, Tianliang Zhao 1, *, Yongqing Bai 2,*, Lijuan Shen 1, Xiaoyun Sun 1 and Yao Gu 1  \n1 Climate and Weather Disasters Collaborative Innovation Center, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, PREMIC, Nanjing University of Information Science&Technology, Nanjing 210044, China; [wyhu_aca@126.com](wyhu_aca@126.com) (W.H.); [20181103046@nuist.edu.cn](20181103046@nuist.edu.cn) (L.S.); [sunxy6362@126.com](sunxy6362@126.com) (X.S.); [guyao@nuist.edu.cn](guyao@nuist.edu.cn) (Y.G.)  \n2 Institute of Heavy Rain, China Meteorological Administration, Wuhan 430205, China  \n* Correspondence: [tlzhao@nuist.edu.cn](tlzhao@nuist.edu.cn) (T.Z.); [baiyq2007@126.com](baiyq2007@126.com) (Y.B.)  \nReceived: 29 October 2020; Accepted: 20 November 2020; Published: 22 November 2020   \n􀀁􀀂􀀃􀀁􀀄 􀀆􀀇􀀈  \n􀀁􀀂􀀃􀀄􀀅􀀆􀀇  \nAbstract: The Twain-Hu basin (THB), covering the lower plain of Hubei and Hunan provinces in Central China, has experienced severe air pollution in recent years. However, the terrain effects of such sub-basin on air quality over the THBhave been incomprehensibly understood. A heavy PM2.5 pollution event occurred over the THB during 4–10 January 2019. By using the observations and WRF-Chem simulations, we investigated the underlying mechanisms of sub-basin effects on the air pollution with several sensitivity experiments. Observationally, air pollution in the western THB urban area with an average PM2.5 concentration of 189.8 􀀖g m􀀀3, which was more serious than the eastern urban area with the average PM2.5 concentration of 106.3 􀀖g m􀀀3, reflecting a different influence of topography on air pollution over the THB. Simulation results revealed that the terrain effect can contribute 12.0% to increasing the PM2.5 concentrations in the western THB, but slightly mitigate the pollution extent in the eastern THB with the contribution of 􀀀4.6% to PM2.5 during the heavy pollution episode. In particular, the sub-basin terrain was conducive to the accumulation of PM2.5 by regional transport with the contribution of 39.1 %, and contrarily lowered its local pollution by 􀀀57.0% via the enhanced atmospheric boundary layer height and ventilation coefficients. Given a heavy air pollution episode occurring over the THB, such inverse contribution of terrain effects reflected a unique importance of sub-basin topography in regional transport of air pollutants for air pollution in central China.  \nKeywords: sub-basin e􀀋ect; PM2.5 pollution; Twain-Hu basin; regional transport; WRF-Chem  \n1. Introduction  \nFor the high PM 2.5 concentrations (i.e., the atmospheric particles with aerodynamic diameters equal to or less than 2.5 􀀖m) in ambient atmosphere [1,2] and its negative e􀀋ects on human health [3,4], PM2.5 variations [5,6], causes [7,8], and the impacts on environment and climate [9,10] have been intensively studied in recent years.  \nAnthropogenic emissions of air pollutants are the primary driver for the increase in PM 2.5 concentrations [11,12], and unfavorable meteorological conditions are the major driver to exacerbate air pollution [13–15] . Four regions are closely associated with heavy air pollution on account of their high emission intensity—the North China Plain (NCP) [16,17], the Yangtze River Delta (YRD) [18,19] in East China, the Pearl River Delta (PRD) [20,21] in South China, and Sichuan Basin (SCB) [22–24] in Southwest China. Adverse meteorological conditions, including weak surface winds, temperature inversion layer,  \nAtmosphere 2020, 11, 1258; [doi:10.3390](doi:10.3390/atmos11111258 www.mdpi.com/journal/atmosphere)[/](doi:10.3390/atmos11111258 www.mdpi.com/journal/atmosphere)[atmos11111258 www.mdpi.com](doi:10.3390/atmos11111258 www.mdpi.com/journal/atmosphere)[/](doi:10.3390/atmos11111258 www.mdpi.com/journal/atmosphere)[journal](doi:10.3390/atmos1111","cbCaijhGGmk9rDca","https://ap.wps.com/l/cbCaijhGGmk9rDca","pdf",3631657,1,12,"English","en",105,"# Abstract\n# Keywords\n# 1. Introduction","[{\"question\":\"What is the main research question of the study?\",\"answer\":\"How sub-basin topography affects air pollution in the Twain-Hu basin, especially by enhancing PM2.5 regional transport during a heavy pollution episode.\"},{\"question\":\"Which tools and data are used to investigate the mechanisms?\",\"answer\":\"The study combines observations with WRF-Chem simulations and applies sensitivity experiments to isolate terrain-related effects.\"},{\"question\":\"How does sub-basin terrain influence PM2.5 in different parts of the Twain-Hu basin?\",\"answer\":\"Terrain increases PM2.5 concentrations in the western urban area (contribution 12.0%), while it slightly mitigates pollution extent in the eastern area (contribution −4.6%) during the heavy episode.\"}]","Contribution of Regional PM 2.5 Transport to Air Pollution Enhanced by Sub-Basin Topography - A Modeling Case over Central China | PDF",1787820311,30,{"code":4,"msg":31,"data":32},"ok",{"site_id":24,"language":23,"slug":33,"title":13,"keywords":34,"description":14,"schema_data":35,"social_meta":87,"head_meta":89,"extra_data":91,"updated_unix":28},"contribution-of-regional-pm-25-transport-to-air-pollution-enhanced-by-sub-basin-topography-a-modeling-case-over-central-china","",{"@graph":36,"@context":86},[37,54,69],{"@type":38,"itemListElement":39},"BreadcrumbList",[40,44,48,51],{"item":41,"name":42,"@type":43,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":45,"name":46,"@type":43,"position":47},"https://docshare.wps.com/document/","Document",2,{"item":49,"name":12,"@type":43,"position":50},"https://docshare.wps.com/document/research-report/",3,{"item":52,"name":13,"@type":43,"position":53},"https://docshare.wps.com/document/contribution-of-regional-pm-25-transport-to-air-pollution-enhanced-by-sub-basin-topography-a-modeling-case-over-central-china/150431/",4,{"url":52,"name":13,"@type":55,"author":56,"headline":13,"publisher":58,"fileFormat":61,"inLanguage":23,"description":14,"dateModified":62,"datePublished":63,"encodingFormat":61,"isAccessibleForFree":64,"interactionStatistic":65},"DigitalDocument",{"name":9,"@type":57},"Person",{"url":41,"name":59,"@type":60},"DocShare","Organization","application/pdf","2026-09-04","2026-08-27",true,{"@type":66,"interactionType":67,"userInteractionCount":20},"InteractionCounter",{"@type":68},"ViewAction",{"@type":70,"mainEntity":71},"FAQPage",[72,78,82],{"name":73,"@type":74,"acceptedAnswer":75},"What is the main research question of the study?","Question",{"text":76,"@type":77},"How sub-basin topography affects air pollution in the Twain-Hu basin, especially by enhancing PM2.5 regional transport during a heavy pollution episode.","Answer",{"name":79,"@type":74,"acceptedAnswer":80},"Which tools and data are used to investigate the mechanisms?",{"text":81,"@type":77},"The study combines observations with WRF-Chem simulations and applies sensitivity experiments to isolate terrain-related effects.",{"name":83,"@type":74,"acceptedAnswer":84},"How does sub-basin terrain influence PM2.5 in different parts of the Twain-Hu basin?",{"text":85,"@type":77},"Terrain increases PM2.5 concentrations in the western urban area (contribution 12.0%), while it slightly mitigates pollution extent in the eastern area (contribution −4.6%) during the heavy episode.","https://schema.org",{"og:url":52,"og:type":88,"og:title":13,"og:site_name":59,"og:description":14},"article",{"robots":90,"canonical":52},"index,follow",{"doc_id":7,"site_id":24},{"code":4,"msg":5,"data":93},[94,98,102,106,111,116,121,123,128,131,135],{"id":20,"doc_module":4,"doc_module_name":46,"category_name":95,"show_sort_weight":96,"slug":97},"Story & Novel",90,"story-novel",{"id":47,"doc_module":4,"doc_module_name":46,"category_name":99,"show_sort_weight":100,"slug":101},"Literature",80,"literature",{"id":53,"doc_module":4,"doc_module_name":46,"category_name":103,"show_sort_weight":104,"slug":105},"Exam",70,"exam",{"id":107,"doc_module":4,"doc_module_name":46,"category_name":108,"show_sort_weight":109,"slug":110},5,"Comic",60,"comic",{"id":112,"doc_module":4,"doc_module_name":46,"category_name":113,"show_sort_weight":114,"slug":115},6,"Technology",50,"technology",{"id":117,"doc_module":4,"doc_module_name":46,"category_name":118,"show_sort_weight":119,"slug":120},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":46,"category_name":12,"show_sort_weight":29,"slug":122},"research-report",{"id":124,"doc_module":4,"doc_module_name":46,"category_name":125,"show_sort_weight":126,"slug":127},9,"Religion & Spirituality",20,"religion-spirituality",{"id":126,"doc_module":4,"doc_module_name":46,"category_name":129,"show_sort_weight":126,"slug":130},"World Cup","world-cup",{"id":132,"doc_module":4,"doc_module_name":46,"category_name":133,"show_sort_weight":132,"slug":134},10,"Lifestyle","lifestyle",{"id":136,"doc_module":4,"doc_module_name":46,"category_name":137,"show_sort_weight":107,"slug":138},19,"General","general"]