Effects of Regional Transport on Haze in the North China Plain: Transport of Precursors or Secondary Inorganic Aerosols. Issue 14 (21st July 2020)

• Record Type: Journal Article
• Authors: Du, Huiyun; Li, Jie; Wang, Zifa; Dao, Xu; Guo, Song; Wang, Lingling; Ma, Shuangliang; Wu, Jianbin; Yang, Wenyi; Chen, Xueshun; Sun, Yele
• Is Part Of: Geophysical research letters. Volume 47:Issue 14(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-07-21
• Subjects: secondary inorganic aerosols -- source apportionment -- transport form -- air pollution -- model simulation; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL087461
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Most previous studies treat regional transport of aerosols as a whole, without distinguishing the transport of secondary aerosols and that of their precursors. A new method of quantifying the transport forms of secondary inorganic aerosols (SIA) using the Nested Air Quality Prediction Modeling System was proposed. The contribution of nonlocal emissions to SIA in the receptor region was divided into three parts: (1) SIA chemically formed by nonlocal emissions in their source regions; (2) SIA chemically formed by nonlocal emissions during transport; and (3) SIA chemically formed by nonlocal emissions in the receptor region, representing transport of precursors. In the North China Plain, the transport of precursors and SIA produced during transport are the two main transport forms. Furthermore, the contribution from transport of precursors increased under polluted conditions in most cities. The results indicate that joint control of precursors is paramount for mitigating air pollution. Plain Language Summary: Uncertainties still exist about the sources of secondary inorganic aerosols (SIA), which are one of the crucial drivers of haze pollution. The spatial distribution of precursors is not exactly consistent with that of aerosols, which is puzzling to policymakers. Most existing studies only treat contribution from regional transport of nonlocal emissions as a whole but do not distinguish the transport of secondary aerosols themselves and that of their precursors. Therefore, it is necessary to quantify the contribution from transport of precursors and secondary aerosols. The Nested Air Quality Prediction Model System with an online tracer‐tagging module was used to investigate the regional sources of SIA in Beijing and surrounding cities. The regional contribution of nonlocal emissions to SIA in the receptor region was divided into three parts: (1) SIA chemically formed by nonlocal emissions in their source region; (2) SIA chemically formed by nonlocal emissions in transport pathway; and (3) SIA chemically formed by nonlocal emissions in the receptor region, indicating transport of precursors. The results showed that transport of precursors and the SIA produced during transport are two main transport forms. The results strongly suggest that the joint control of precursors is important for mitigating air pollution. Key Points: A new method of quantifying the transport forms of secondary inorganic aerosols (SIA) using an air quality model was proposed The transported SIA in the receptor region is from conversion of nonlocal emissions in the source region, transport path, and receptor region The chemical conversion of nonlocal emissions after they leave their source region is crucial in the North China Plain