2018年冬季淄博市一次沙尘天气颗粒物污染特征研究

2018年11月底淄博市经历了一次沙尘影响下的大气重污染过程，为研究此次重污染过程形成机制，分析了淄博市ρ(PM₁₀)和ρ(PM_2.5)及PM_2.5化学组分特征，并利用PMF模型和后向轨迹模型对颗粒物的来源进行研究.结果表明:①污染期间，ρ(PM₁₀)和ρ(PM_2.5)小时平均值分别为(259±111)和(133±51)μg/m3，分别是污染后ρ(PM₁₀)〔(88±38)μg/m3〕和ρ(PM_2.5)〔(36±14)μg/m3〕的2.9和3.7倍.②受沙尘的影响，Ca2+、Mg2+、Al、Mg、Ca、Si等代表沙尘源的离子和元素组分的质量浓度在PM_2.5中占比均高于污染后.③ 72 h后向轨迹结果表明，除受西北方向沙尘传输气流影响外，局地盘旋的当地气流也增加了污染物的累积，此次大气污染过程是本地污染物累积及西北沙尘传输共同作用形成的.④ PMF模型解析表明，污染期间扬尘源是PM_2.5的首要贡献源类，贡献率达33.61%，说明沙尘过境对此次污染过程有较大贡献；污染后工业源贡献显著增高，成为主要污染源，贡献率为22.71%，体现了淄博市是重工业城市的特点.研究显示，淄博市此次重污染过程颗粒物来源复杂，除受本地区域污染影响外，外来沙尘过境贡献也较大. 

Characteristics of Atmospheric Particulate Matters During Winter Sandstorm Period in 2018 in Zibo City

At the end of November 2018, Zibo City experienced a heavy atmospheric pollution episode caused by the influence of sand and dust. In order to study the formation mechanism of the particulate matters during the heavy pollution, the concentrations of PM₁₀ and PM_2.5 and the chemical composition of PM_2.5 were analyzed. The source of particulate matter was studied using the PMF model and the backward trajectory model. The results showed that: (1) During the pollution period, the average concentrations of PM₁₀ and PM_2.5 were (259±111) and (133±51)μg/m3, respectively, which were 2.9 and 3.7 times higher than the period after pollution. (2) Affected by sand and dust, Ca2+, Mg2+, Al, Mg, Ca, Si, etc. represented the ion and element components of sand and dust sources, and their mass concentrations in PM_2.5 were higher than that after pollution. (3) The 72 h backward trajectory showed that the accumulation of pollutants was attributed to the locally circling air mass and the long-range dust transportation from the northwest. The air pollution process was the combined result of pollutant accumulation and northwest dust transportation. (4) The PMF results showed that the dust source was the primary source and contributed to 33.61% of PM_2.5 during the pollution period, indicating that sand dust played an important role in this pollution process. After the pollution process, the contribution of industrial sources increased significantly, accounting for 22.71% of the pollution, reflecting the characteristics of Zibo City as a heavy industry city. The results indicate that the source of particle in the heavy pollution period in Zibo City is complex, which is not only affected by the local regional pollution, but also greatly affected by dust migration.