Atmospheric pollutants including NO_x,O₃ and PM_2.5,along with meteorological factors were intensively monitored in Luhuitou village of Sanya,which is the southernmost tip of Hainan Island,in order to study the characteristics of air pollution in Sanya.Located in the outskirt of Sanya,the monitoring station is surrounded by sea in three directions and without industrial pollution sources.From December of 2011 to April of 2013,the variation properties of NO_x,O₃ and PM_2.5 in winter and spring were analyzed and the sources of pollutants were investigated using backward trajectory method.The results show that,the concentrations of air pollutants in Sanya were under the values listed as first level in national standard,with the daily average value of NO,NO₂,NO_x,O₃,and PM_2.5 being (2.1±2.2),(5.2±3.4),(7.3±3.8),(59.8±28.4),and (17.5±14.3)μg·m^-3,respectively.The diurnal variations of NO_x and PM_2.5 showed double-peak patterns,with the maximum concentrations appeared at 08:00 BJ (Beijing time) and 17:00 BJ;while the diurnal variation of O₃ exhibited a single peak which occurred at 13:00 BJ.Based on backward trajectory method,it was found that pollutants in Sanya came from local and regional sources,and the continental air mass usually led to accumulation of air pollutants,whereas the marine air masses usually diluted the air pollution.