2016~2018年采暖季太行山沿线城市PM2.5污染特征分析

对2016年、2017年采暖季太行山沿线传输通道城市大气中PM_2.5的OC、EC和水溶性离子进行分析，并利用特征组分比值和元素富集因子变化研究该传输通道的污染特征.结果表明，2017年采暖季通道整体较2016年同期空气质量改善良好，PM_2.5浓度由2016年的171.86μg/m³下降为123.90μg/m³.太行山中部城市2017年采暖季较2016年同期PM_2.5浓度下降显著，2a采暖季SNA离子（SO^2-，NO₃^-，NH₄⁺ 3种离子总称）浓度与占比呈现"北低南高"，加之SNA/EC比值"北低南高"，表明南部城市二次无机生成较为严重.而OC、EC浓度与占比呈现"北高南低"，Cl^-/K⁺比值和元素Zn、Ba的富集因子北部均高于南部，表明北部城市可能受燃煤和机动车源等一次排放影响较大；各城市2017年采暖季SO₂、NO₂、CO浓度有所下降，且均呈现"北高南低"趋势，进一步表明北部城市一次排放较为严重.

Characteristics of PM2.5 in cities along the Taihang Mountains during the heating season of 2016~2018

The OC, EC and water-soluble ions in PM_2.5 in the urban atmosphere along the transmission channel of the Taihang Mountains in the heating season of 2016 and 2017 was analyzed. Pollution characteristics were explored by using the characteristic components ratio and element enrichment factor. The results showed that the air quality in the 2017 heating season was better than that in the same period of 2016. PM_2.5 concentration decreased from 171.86μg/m³ to 123.90μg/m³. Compared with the same period of 2016, the PM_2.5 concentration in the central city of Taihang Mountain decreased significantly during the heating season in 2017. The character of SNA ions concentratiosn and ratio in the two-year heating season was "low in north and high in south", and the SNA/EC ratios were the same trend, which indicating that the secondary inorganic formation in the south cities was sever than it in north. Oppositely, the concentrations of OC and EC and ratio were "high in the north and low in the south". The Cl^-/K⁺ ratio and the enrichment factors of Zn and Ba were higher in the north, indicating that the northern cities might be affected heavily by primary emissions such as coal combustion and vehicles. The concentration of SO₂, NO₂ and CO in the heating season of each city declined in 2017, further indicating that the primary emissions in the northern cities were more serious.