Chemical Compositions, Sources, and Intra‐Regional Transportation of Submicron Particles Between North China Plain and Twain‐Hu Basin of Central China in Winter

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Regional submicron particles (PM 1 ) compositions, sources, and interaction are still not clear as the desynchrony in observation. This study focused on PM 1 at five sites synchronously in North China Plain and Central China during January 2018. The average PM 1 mass concentrations decreased from north to south, with higher values in Luohe (125 ± 59.4 μg m −3 ), followed by borderline cities (54.1–93.3 μg m −3 ) and a south site of Wuhan (63.6 ± 21.5 μg m −3 ). Organic matter (41.8%–51.0%) and secondary inorganic aerosols (SIAs; 28.2%–33.2%) occupied the high fractions for all the five sites. Coal combustion and industrial processes mainly raised the differences in PM 1 chemical compositions between regions. The changes of NO 3 − /SO 4 2− between sites were different as a function of relatively humidity and temperature, reflecting the differences of secondary formation mechanism. For a short intraregional transport case from south to north, PM 1 increased from 102 to 185 μg m −3 as the accumulation and aerosol‐planet boundary layer interaction under a stable meteorological condition. For a long‐range transport case from north to south with a high wind speed (5.5 m s −1 ) and boundary layer height (529 m), PM 1 decreased by only 0.9 μg m −3 (−1.3%) as the enhanced formation of SIA by 12.6% under increased relative humidity (by 7.2%) and enhanced industrial emission (by 19.1%) at the south site. The results provide a useful data set for modeling PM 1 chemical compositions and their impacts and are helpful for regional‐joint control of atmospheric particles and precursor gases.