北京野鸭湖湿地观测站PM_2.5变化特征及其与气象因素的关系

Changing Characteristics of PM_2.5 in Beijing Wild Duck Lake Wetland Station and Its Relationship with Meteorological Factors

利用北京野鸭湖湿地观测站2014~2016年PM2.5和同期气象观测资料,分析野鸭湖地区PM2.5的变化特征及气象影响因素。研究结果表明:野鸭湖观测站PM2.5年平均浓度为40 μg?m?3,3年来超标比例下降61.6%。PM2.5污染夏季最轻,春秋次之,冬季最重,各月中PM2.5浓度2月份达到峰值,9月最低。各季PM2.5日变化大致为双峰型,春冬季更为明显。PM2.5日均浓度与相对湿度和气压呈正相关,与气温和风速呈负相关,其中与相对湿度相关性最高;各季略有差别,PM2.5在夏季与气温呈正相关且气压为主导因素,秋季PM2.5与气压显负相关,其余与日浓度表现一致。野鸭湖地区PM2.5浓度受本地源和外来源的共同影响,东北风和东北偏东风易造成PM2.5积累,西南偏西风控制下PM2.5浓度在各季节中达到最低。

Date collected from 2014-2016 was analyzed to study the PM2.5 concentration and correlated factors in Wild Duck Lake wetland ecological meteorological station. The results showed that the average concentration of PM2.5 was 40 μg?m?3, the exceeding rate of Grade II air quality standards decreased 61.6% over the three years. The seasonal comparison indicated that PM2.5 pollution was the lowest in summer and heavy in winter. The concentration of PM2.5 was the highest in January, the lowest in September. The average diurnal variations of PM2.5 show two peaks, while the characteristic of two peaks was more significant in spring and winter. The daily concentration of PM2.5 had a positive correlation with relative humidity and air pressure, negative correlation with temperature and wind speed. The humidity was significant factor for PM2.5. The PM2.5 concentration was different correlation with meteorological factors in every season. In summer, PM2.5 had a positive correlation with temperature, meanwhile, the air pressure was the dominant factor. The air pressure had a negative correlation with PM2.5 in autumn. The remaining characteristics in the seasons were consistent with daily concentrations of PM2.5. The PM2.5 in Wild Duck Lake combined impact by local pollution and external pollution. When the station controlled by northeaster and east-northeast can cause more PM2.5 accumulation, however, the west-southwest has exactly the opposite.