济南市大气细颗粒物中二(口恶)英污染水平及季节变化

2021年对济南市大气PM_2.5中17种2,3,7,8氯取代二(口恶)英(PCDD/Fs)污染现状进行监测。对其异构体分布、指示性单体、季节变化规律等特征及其与常规污染物相关性进行了分析。结果表明:大气PM_2.5中PCDD/Fs浓度范围和年平均值分别为0.157~1.595 pg/m³和0.785 pg/m³,而毒性当量(以I-TEQ计)范围和年平均值分别为0.009~0.116 pg TEQ/m³和0.052 pg TEQ/m³。PCDD/Fs浓度与毒性当量季节变化特征显著,均呈现出冬季>春季>秋季>夏季的情况,可能由季节性排放源和气象条件不同导致。不同季节PCDD/Fs异构体分布模式一致,主要由高氯代(1,2,3,4,6,7,8-HpCDF、OCDD、OCDF和1,2,3,4,6,7,8-HpCDD)单体组成;而对毒性当量贡献最大的单体是2,3,4,7,8-PeCDF,其与总毒性当量具有较好的相关性。同时,PCDD/Fs浓度与SO₂、NO₂、PM_2.5等大气常规污染物呈显著正相关。这表明,大气PM_2.5中PCDD/Fs与常规污染物的生成和排放密切相关。

Levels and Seasonal Variation of Dioxin in Atmospheric Fine Particle in Jinan City,China

The pollution profiles,indicated congeners and seasonal variations of 17 species,2,3,7,8 -PCDD/Fs in PM_2.5 of Jinan were inves tigated from January to October 2021.Meanwhile,correlation analysis was conducted between PCDD/Fs and other air pollution parameters such as SO₂,NO₂,PM_2.5.The results showed that the PCDD/Fs mass concentrations varied from 0.157 to 1.595 pg/m³ (annual average 0.785 pg/m³).Further,TEQ calculated by I-TEQ ranged from 0.009 to 0.116 pg TEQ/m³ (annual average 0.052 pg TEQ/m³).The significant seasonal changes were observed,higher levels appeared in winter than in summer,which might be affected by meteorological condition and emission source during the sampling period.The distribution of PCDD/Fs were temporally highly similar in four seasons,the dominant congeners were 1,2,3,4,6,7,8-HpCDF,OCDD,OCDF and 1,2,3,4,6,7,8-HpCDD,and the largest contributor to total TEQ was 2,3,4,7,8-PeCDF.The high correlation coefficients of the concentration of PCDD/Fs with that of SO₂,NO₂ and PM_2.5 indicated that atmospheric PCDD/Fs might beclosely related to the generation and discharge of conventional pollutants.