石家庄市冬季PM2.5污染特征、成因及潜在源区分析

Characteristics, Causes and Potential Source Regions of PM25 Pollution in Winter in Shijiazhuang, China

  • 摘要: 对石家庄市2016年1月18-22日出现的PM2.5污染过程进行研究,选择3个不同地区采用中流量采样器分别采集PM2.5和PM10样品,测定PM2.5质量浓度及其化学组分(含碳组分、水溶性离子和无机元素),分析PM2.5污染天气的污染特征和引起污染的气象因素,结合后向轨迹模型(HYSPLIT)分析污染的主要潜在源区。结果显示,在采样期间3个点的PM2.5平均质量浓度分别为113、131和119 μg·m-3,PM2.5浓度高值出现在早晨和午夜,冬季京津冀地区农村散煤燃烧也是大气污染的主要原因。有机碳(OC)最大质量浓度值为218.37 μg·m-3,无机碳(EC)最大质量浓度值为21.22 μg·m-3。污染过程中3个点的地壳元素(Na、Ca、Mg、Al、K和Fe)质量浓度变化范围为27.19~60.03 μg·m-3,占总无机元素的96.5%,表明交通源、道路扬尘和煤炭燃烧是此次石家庄市PM2.5污染的主要贡献源类。较高的相对湿度和弱风速也会加速二次粒子的生成和颗粒物吸湿增长。潜在源分析表明,石家庄市PM2.5污染主要受来源于北京和天津的气团影响,同时潜在源贡献(PSCF)分析表明河北省是影响石家庄市环境空气质量的最主要潜在源区。

     

    Abstract: Study was carried out of the pollution of PM2.5 and PM10 occurring during the period from January 18 to 22, 2016 in Shijiazhuang, China. For the study, 3 monitoring posts were set up to collect PM2.5 and PM10 samples for analysis of mass concentration and chemical compositions (including carbon fractions, water soluble ions and inorganic elements), pollution characteristics and meteorological factors responsible for the pollution and further for air parcel back trajectories using HYSPLIT. Results show that mean mass concentration of PM2.5 with the three monitoring posts reached 113, 131 and 119 μg·m-3, separately, during the sampling period, with high mass concentrations observed in the early mornings and at noons, and coal combustion in rural farm households was also a main cause of heavy air pollution in the region of Beijing-Tianjin-Hebei. The highest mass concentration of organic carbon (OC) observed was 218.37 μg·m-3, and the highest mass concentration of inorganic carbon (IC) 21.22 μg·m-3. Total concentrations of crustal elements (Na, Ca, Mg, Al, K and Fe) varied in the range from 27.19 to 60.03 μg·m-3 at the three posts during the period, accounting for 96.5% of the total inorganic elements, which indicate that traffic, road dust and coal combustion are the main sources of the air pollution. Meanwhile, high relative humidity and low wind speed might also accelerate formation of secondary particles and hygroscopic growth. The analysis of potential sources shows that Shijiazhuang was affected mainly by the PM2.5 coming with the air masses from Beijing-Tianjin, meanwhile the analysis of potential source contribution function (PSCF) shows that Hebei Province was the uppermost potential source-area contributing adversely to the atmospheric quality in Shijiazhuang.

     

/

返回文章
返回