Real-time measurements of non-refractory submicron aerosols (NR-PM1) were conducted using an aerodyne mass spectrometry (Q-AMS) at the summit of Mount Tai (1534m above sea level)in Shandong province,locates in the center of the Central East China (CEC) region,from June 2010 to January 2012,as a part of National basic research project monitoring campaign.The mass concentrations and size distributions of non-refractory submicron particle (NR-PM1) species (i.e.,sulfate,nitrate,ammonium,chloride,and organics) were measured in situ at 5-min time resolution.Overall,146 days valid data was obtained during the whole campaign,which covers four different seasons.The average total mass concentration of NR-PM1 was 42.9 g m-3,with 31%sulfate,32% organics,19% nitrate and 18% ammonium.The average mass concentration of NR-PM1 is highest (59.9 g m-3) in summer and lowest (31.9 g m-3) in spring.Species occupied different percentages in different seasons,sulfate in summer,Organics in fall and winter,while nitrate dominants the NR-PM1 in spring respectively.To investigate the size-resolved mass concentrations of aerosol chemical components from different sources,seven air masses were clustered based on the 72 hours back trajectory with HYSPLIT model.Cluster I,IV and V with short pathway represent the local and regional sources,and the concentrations from these clusters were higher than that from cluster III and VI which originated from remote and clean North-West sources.According to the results of diurnal cycles for chemical species in NR-PM1 higher at noon and lower at midnight from seven clusters,it was concluded that the site was controlled under the transitions between PBL and FT at daytime and nighttime.The size distributions of chemical species were different from different air masses,cluster I,II,IV,V and VII showed same shape with accumulation mode (500-600nm),the concentration at nighttime is lower than at daytime.For cluster VI and III,it demonstrated wider shape peaking at 300 nm,and there were no obvious decrease in concentration at nighttime.