首页|Enhancement and Removal of PM2.5 by Cold and Warm Air Masses Accompanying Certain Synoptic Weather Systems across Hangzhou,China during 2014-2020

Enhancement and Removal of PM2.5 by Cold and Warm Air Masses Accompanying Certain Synoptic Weather Systems across Hangzhou,China during 2014-2020

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Local air pollution is strongly affected by synoptic weather systems,such as fronts,troughs,low-altitude vortices,or high-altitude ridges.Nevertheless,few studies have analyzed the meteorological properties of cold or warm air masses associated to these systems and their impact on local air quality.In this study,hourly observations of fine par-ticulate matter(diameter of up to 2.5 pm,i.e.,PM2.5),wind(V),temperature(T),pressure(P),and precipitation(R),acquired in Hangzhou in 2014-2020,were analyzed.From this analysis,weather patterns were categorized into 27 types;89 and 94 cases illustrating the passage of warm and cold air masses over Hangzhou were identified,respect-ively;the influence of air mass temperature,wind speed,and wind direction on PM2.5 concentrations and local accu-mulation or removal was quantified.The main results are as follows.(1)Pollution events occurred more frequently for cold than for warm air masses,but average pollutant concentration was lower for cold air masses;(2)48%of the cold air mass cases corresponded to PM2.5 decreases and 52%to PM2.5 increases,with strong cold air masses(ΔT24h>4℃;|V|average>4 m s-1)markedly reducing local pollution,but weak cold air masses(ΔT24h<2℃;|V|average<2 m s-1)primarily inducing pollutant transport and accumulation;(3)for warm air masses,PM2.5 accumu-lation or removal occurred in 60%and 40%of the cases,respectively:warm air masses(ΔT24h>4℃)reduced the PM2.5 concentration whereas weaker winds(|V|average<2 m s-1)increased it;and(4)PM2.5 concentration decreased sharply within 4 h after the passage of strong cold air masses,but more gradually within 14 h after the passage of strong warm air masses.These results considerably improve the current understanding of the influence of cold and warm air masses on local pollution patterns.

weather typeair massenhancementremovalmeteorological condition

Bu YU、Feng CHEN、Hanqing KANG、Bin ZHU、Hongnian LIU

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Hangzhou Meteorological Bureau,Hangzhou 310051

Hangzhou International Urbanology Research Center for Urban Governance Studies,Hangzhou 311121

Zhejiang Institute of Meteorological Sciences,Hangzhou 310008

Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science & Technology,Nanjing 210044

School of Atmospheric Sciences,Nanjing University,Nanjing 210023

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State Scholarship Fund of ChinaNational Natural Science Foundation of ChinaHangzhou Science and Technology Development Project

202305330011419750042022ZDSJ0298

2024

气象学报(英文版)
中国气象学会

气象学报(英文版)

CSTPCD
影响因子:0.57
ISSN:0894-0525
年,卷(期):2024.38(3)