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

Regional submicron particles (PM1) 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 PM1 mass concentrations decreased from north to south, with higher values in Luohe (125 +/- 59.4 mu g m(-3)), followed by borderline cities (54.1-93.3 mu g m(-3)) and a south site of Wuhan (63.6 +/- 21.5 mu g 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 PM1 chemical compositions between regions. The changes of NO3-/SO42- 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, PM1 increased from 102 to 185 mu g 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), PM1 decreased by only 0.9 mu g 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 PM1 chemical compositions and their impacts and are helpful for regional-joint control of atmospheric particles and precursor gases.