中文摘要：

在天津市环境监测超级站利用在线OC/EC分析仪对2015年3月27-28日发生在中国北方的一次典型沙尘污染过程进行了观测,使用OC/EC（有机碳/元素碳）最小比值法估算二次有机碳（SOC）的贡献。结果显示,本次沙尘过程中PM10的小时浓度出现两次峰值,最高达895μg/m~3,PM_2.5/PM_10在沙尘天气期间（0.08~0.22）明显低于非沙尘天气（0.66）;OC、EC的浓度在PM10浓度出现第一次峰值时达到最低,OC/EC在沙尘天气时约为非沙尘天气的2倍;SOC在沙尘天气前约占OC的45%,在沙尘发生时上升至75%。沙尘天气下,OC、EC的浓度有消减的趋势,在沙尘初期消减量分别达到39%和74%;其对一次有机碳（POC）的消减作用要高于SOC。

英文摘要：

A continuous observation on the typical dust storm （DS） pollution process from March 27th to 28th,2015 in north of China,was conducted with semi-continuous OC/EC （organic carbon/elemental carbon） aerosol analyzer in the super monitoring station in Tianjin. The results showed that two concentration peaks of PM10 appeared,with a highest hourly concentration of 895 μg/m3 together.The ratio of PM25 and PM10 （0.08-0.22） in the period of DS was below that （0.66） in the period of non-DS distinctly. The lowest concentration of OC and EC came into being along with the emergence of the first PM10 concentration peak. The ratio of OC and EC in DS episode was about 2 times higher than that before DS occurred. Secondary organic carbon （SOC） accounted for about 45% of OC before DS, and 75% when DS occurred. The results demonstrated that DS helped to decrease the concentrations of OC and EC.At the beginning of DS weather,the concentrations of OC and EC decreased most,about 39% and 74% respectively.Additionally,the DS had more influences on primary organic carbon （POC） than on SOC, the absolute mass concentration of POC decreased by 74%,while the SOC increased steadily.