A single particle aerosol mass spectrometer was deployed to measure the changes of single particle species and sizes during March 2015 in Weizhou Island of the Beibu Gulf,Guangxi province,South China.In this campaign,a total of 3,100,597 particles were sized,and 25.8％ particles with both positive and negative mass spectrum were collected and 24.8％ characterized in combination with the ART-2a neural network algorithm.The distribution of sized particles was mainly in from 520 to 600 nm,and the diameters ranging from 340 to 1000 nm accounted for above 90％.Eight types of particles were classified:Elemental Carbon containing (EC),Organic Carbon containing (OC),EC and OC combined containing particles,Na containing particles,K containing particles (K),Levoglucosan containing particles,mineral containing particles,and Heavy Metal containing particles (HM).EC,OC and K were the major containing particles,which accounted for 84.3％ in the eight types particles.The relative ratio and size distribution of the three types were EC (48.1％,620 nm),OC (12.7％,440 nm),and K (23.5％,600 nm),respectively.The three types of particles were a bit increasing ratios compared with those in clean periods during haze pollution periods.Combined with the back-trajectory results from the Hysplit-4 model and local pollution sources revealed that the ambient air quality on the Weizhou Island may be influenced by biomass bing in the Indochina Peninsula (biomass bing in the Indochina Peninsula)from the transportation on higher level atmospheric layer and by mainland of south China located northeast of Weizhou Island on the ground.