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Insights into quantitative evaluation technology of PM 2.5 transport at multi-perspective and multi-spatial and temporal scales in the north China plain.
- Source :
-
Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2023 Dec 01; Vol. 338, pp. 122693. Date of Electronic Publication: 2023 Oct 04. - Publication Year :
- 2023
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Abstract
- Cross-border transport is a crucial factor affecting air quality, while how to quantify the transport contribution through different technologies at multi-perspective and multi-scale have not been fully understood. This study established three quantification techniques, and conducted a systematic assessment of PM <subscript>2.5</subscript> transport over the North China Plain (NCP) based on numerical simulations and vertical observations. Results suggested that the annual local emissions, inter-urban and outer-regional transport contributed 44.5%-64.6%, 15.2%-27.9% and 18.0%-28.2% of total surface PM <subscript>2.5</subscript> concentrations, respectively, with transport intensity stronger in July and April, yet weaker in January and October. The southwest-northeast, northeast-southwest, and southeast-northwest were three prevailing transport directions near the surface. By comparison, the annual PM <subscript>2.5</subscript> transport contribution below the atmospheric boundary layer height increased by 16.8%-24.5% in Beijing, Tianjin and Shijiazhuang, with inter-urban and outer-regional contribution of 29.8%-32.1% and 18.5%-23.1%. Furthermore, observed fluxes from fixed-point and vehicle-based mobile lidar were in good agreement with the simulated flux. PM <subscript>2.5</subscript> net flux intensity varied with height, with generally larger at the middle- and high-altitude layer than that of low-altitude layer. In the early, during and late period of haze peak formation (Stage Ⅰ, Ⅱ, Ⅲ, respectively), the largest absolute flux intensity on average was Stage Ⅱ (566.7 t/d), followed by Stage Ⅲ (307.0 t/d) and Ⅰ (191.4 t/d). Besides, external transport may dominate the second concentration peak, while local emissions may play a more vital role in the first and third peaks. It has been noted that joint prevention and control measures should be proposed 1-2 days before reaching PM <subscript>2.5</subscript> extremes. These findings could improve our understanding of transport influence mechanism of PM <subscript>2.5</subscript> and propose effective emission reduction measures in the NCP region.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2023 Elsevier Ltd. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1873-6424
- Volume :
- 338
- Database :
- MEDLINE
- Journal :
- Environmental pollution (Barking, Essex : 1987)
- Publication Type :
- Academic Journal
- Accession number :
- 37802287
- Full Text :
- https://doi.org/10.1016/j.envpol.2023.122693