中文摘要：

大气污染物PM_（2.5）对空气质量造成严重危害,威胁着人类健康。根据西安市13个监测区2013年1月1日—4月26日的PM_（2.5）质量浓度数据,得出西安市PM_（2.5）的浓度呈冬季高、春季低的特点。结合西安市的海拔数据、气象资料,并引入污染系数,分析得出了西安市13个监测区PM_（2.5）的浓度有以下规律：从西到东递减;分布与海拔高度和风向特点相一致;与平均温度、最高温度、最低温度均呈现负相关关系,但相关性不是很高。这为PM_（2.5）的针对性治理工作提供了理论指导。

英文摘要：

The atmospheric pollutants PM_（2.5） do serious harm to air quality,and threat the health of human. According to the concentration data of PM_（2.5） on January 1st,2013 to April 26 in thirteen monitoring areas in Xi＇ an City,we obtained that the concentration of PM_（2.5） in Xi＇an is higher in winter and lower in spring. Combined with the elevation and meteorological data of Xi＇an,and through introducing the pollution coefficient,the concentration of PM_（2.5）in Xi＇ an in thirteen monitoring areas has been analyzed and the following rule was concluded. The concentration of PM_（2.5） diminishes from west to east. The distribution of PM_（2.5） is consistent with the characteristics of altitude and wind direction. The concentration of PM_（2.5） presents a negative correlation with average temperature,maximum temperature and minimum temperature,but the correlation is not so high. This provides a theoretical guidance for pertinence governance of PM_（2.5） for Xi＇an City.