Temporal and Spatial Variation of PM2.5 Concentration in the Pearl River Delta Urban Agglomeration from 2000 to 2022

WU Chubing; XIAO Fuan; DENG Yujiao; WU Zhifeng

doi:10.16032/j.issn.1004-4965.2026.006

Abstract：Previous studies based on observation stations have not fully revealed the spatiotemporal characteristics of PM2.5 concentrations.This paper evaluates the accuracy of PM2.5 remote sensing inversion data in the Pearl River Delta(PRD)urban agglomeration and further explores the spatiotemporal patterns and influencing factors of annual,seasonal,and monthly average PM2.5 concentrations based on the remote sensing inversion data.Validation from 2015 to 2022 confirms the high accuracy of the remote sensing data(R2:0.964-0.998).Analysis based on the inversion data from 2000 to 2022 reveals a"rise-stagnation-decline"trend in annual average PM2.5 concentrations,with key turning points in 2004 and 2013(R2=0.943 6).The primary influencing factors are government policies.Spatially,PM2.5 concentrations exhibit a distinct"high in the center,low in the periphery"pattern.The Guangzhou-Foshan border forms the core pollution zone for PM2.5,while the regions with the lowest pollution levels are identified in Zhuhai,southeastern Huizhou,and southern Jiangmen.Seasonally,PM2.5 concentrations follow a"high in autumn and winter and low in spring and summer"pattern.Taking the high pollution period(2003-2014)as an example,monthly average concentrations of PM2.5 showed a trend of"falling first and then rising"throughout the year,with the highest in January(62.55 μg·m-3)and the lowest in July(22.53 μg·m-3),with precipitation being the main influencing factor.Spatially,from October to January,the area of high PM2.5 concentrations expands southward to encompass Jiangmen and Zhuhai,with significant regional variations.The findings of this study provide theoretical basis for the joint prevention and control of air pollution in urban agglomerations.