石家庄地区芳香族化合物的污染特征及来源分析

为了解石家庄地区芳香族化合物的污染特征,于2016年9月18日至10月17日进行为期30 d的PM_(2.5)样品昼夜采集,使用气相色谱-质谱联用仪(GC-MS)进行定性定量分析.结果表明,芳香族化合物的总平均浓度为33. 5 ng·m~(-3),明显低于左旋葡聚糖(487 ng·m~(-3)).其中硝基酚类化合物浓度最高(20. 4 ng·m~(-3)),芳香酸类次之(9. 94 ng·m~(-3)),芳香醛类最低(3. 14ng·m~(-3)).受边界层高度、温度降低的影响,8种化合物夜间浓度明显高于日间.硝基酚类、芳香醛类和芳香酸类化合物与左旋葡聚糖呈显著的正相关关系,相关性系数(r)分别为0. 682 9、0. 644 3和0. 678 2,表明生物质燃烧是芳香族化合物的重要一次来源,直接影响其在大气中的浓度水平.结合芳香族化合物总浓度的日变化趋势和后向轨迹模型对其来源进行分析,发现秋季石家庄地区芳香族化合物的污染程度受区域传输和本地排放的综合影响.

Pollution Characteristics and Source Analysis of Aromatic Compounds in Shijiazhuang

To understand the pollution characteristics of aromatic compounds in Shijiazhuang, PM_2.5 samples were collected day and night for 30 days from September 18 to October 17, 2016. Qualitative and quantitative analyses were conducted using gas chromatography-mass spectrometry (GC-MS). The results showed that total average concentration of aromatic compounds was 33.5 ng·m^-3, lower than that of levoglucosan (487 ng·m^-3). Concentration of nitro-aromatic compounds was the highest (20.4 ng·m^-3), followed by aromatic acids (9.94 ng·m^-3) and aromatic aldehydes (3.14 ng·m^-3). Influenced by the decrease in the boundary layer and temperature, concentration of 8 substances during night was higher than during the day. There was a significant positive correlation between levoglucosan and nitro-aromatic, aromatic aldehyde, and aromatic acid compounds, with correlation coefficients (r) of 0.6829, 0.6443, and 0.6782, respectively, indicating that biomass burning is an important primary source of aromatic compounds that directly affects their concentrations in the atmosphere. Based on the analysis of daily variation trends in total concentration of aromatic compounds and the backward trajectory model, it was found that the pollution of aromatic compounds in Shijiazhuang in autumn was affected by regional transportation and local emissions.