2013年河北中南部PM_(10)和PM_(2.5)浓度时间变化特征及其影响气象条件分析

Analysis of Temporal Variation Characteristics and Meteorological Conditions of PM_(10) and PM_(2.5) in the South-Central of Hebei Province in 2013

对2013年河北省中南部的石家庄、保定、沧州、衡水、邢台和邯郸6个地市市区各站点逐小时PM10和PM2.5监测资料及相应气象资料分析结果表明:6个地市中邢台年污染日数最多,对应其年平均风速最小;沧州的最少,年平均风速最大。各地市各个级别污染日数不同,五、六级重污染天气均集中在10月—次年3月。首要污染物主要是PM10和PM2.5,但比例不尽相同。特殊的地理位置、污染源差异和气象条件的差异造成各地市污染日数、级别的差异。6个地市污染天气过程时段大都相同,区域性污染明显。各地市PM10和PM2.5浓度平均最大值均出现在冬季,PM10浓度平均最小值均出现在夏季,各市PM2.5浓度平均最小值出现的季节不同。6个地市PM10和PM2.5浓度值的月变化趋势相似。不同季节各地市PM10和PM2.5浓度日变化趋势不同,极值出现的时间也各不相同,极值出现的时间与气象条件和人类活动关系密切。秋、冬季各地市PM10和PM2.5浓度日较差多大于春、夏季的。各地市PM10和PM2.5浓度日均值与当地的日均气温、风速、能见度呈负相关关系,与相对湿度呈正相关关系且相关性比较显著。

The hourly-monitored data of PM10 and PM2.5 in 2013, along with the corresponding meteorological data, in six cities of the south-central of Hebei province, including Shijiazhuang,Baoding, Cangzhou,Hengshui,Xingtai and Handan were examined. The analysis results showed that Xingtai had the most polluted days corresponding to the lowest wind speed while Cangzhou had the least correlating to the highest wind speed. In addition, heavy-pollution days, i.e. Class V and VI, eoneentrated between October and the following March, with primary pollutants being PM10 and PM2.5, while the proportions of pollutants varied from city to city. Such variations in pollution days and classes were dependent on loca- tion, source of pollution, and meteorological characteristics of the observed cities, featuring the similarity in pollution seasons and a strong regional phenomenon. The maximum average concentrations of both PM10 and PM2.5 in all cities occurred in winter, however, the minimum average showed different patterns, with PMjo all in summer while PM2.5 in different seasons in the six cities. Monthly variations of PM10 and PM2.5 concentrations appeared to be similar in general, but the daily variations differed between seasons. So was the emergence time of peak points, which were closely related to meteorological conditions and human activities. Furthermore, the diurnal range of PM10 and PM2.5 is greater in autumn and winter than in spring and summer. Finally, The daily average of PM10 and PM2.5 concentration negatively responded to the local daily average temperature, wind speed and visibility, whereas responded to the relative hu- midity positively, with significant correlation to the latter.