关中地区大气臭氧污染变化特征及其来源解析

关中城市群发展基础较好和开发潜力较大,是中国西部地区的重要经济和文化中心. 近年来关中地区空气质量的持续改善受到了近地面臭氧（O₃）问题的显著影响,为采取有效措施防治O₃污染,基于2018~2021年环境监测数据分析关中地区O₃浓度年、月及日变化等特征规律；采用地理探测器研究O₃浓度空间分异的驱动因素,通过后向轨迹模型和排放因子法等方法解析O₃来源. 结果表明,关中地区O₃浓度日、月变化呈单峰型特征,日最高值出现在15：00,最低值出现在07：00,月均峰值出现在6月,谷值出现在12月,O₃浓度夏季最高,春季次之、冬季最小；O₃超标天数中以轻度污染为主,且中度及以上污染呈先下降后增加趋势；关中地区O₃浓度主要与前体物和气象因素关系密切,且各因子交互作用的解释力显著大于单一因子；关中地区O₃浓度区域传输主要受偏东向气流影响,其次是西北方向,潜在源区主要在河南省和湖北省；挥发性有机物（VOCs）本地主要来源为溶剂使用源、工艺过程源和移动源,氮氧化物（NO_x）主要排放源为移动源和工业生产燃烧源. 研究结果对关中地区O₃科学防控具有指导意义.

Variation Characteristics and Source Analysis of Atmospheric Ozone Pollution in Guanzhong Region

Guanzhong urban agglomeration has a good development foundation and great development potential, and it has a unique strategic position in the national all-round opening up pattern. In recent years, the problem of near-surface ozone （O₃） in the Guanzhong Region has become increasingly prominent, which has become a bottleneck affecting the continuous improvement of air quality. In order to effectively prevent and control O₃ pollution, this study analyzed the characteristics of annual, monthly, and daily changes in O₃ concentration in the Guanzhong Region based on the environmental monitoring data from 2018 to 2021. A geo-detector was used to study the driving factors of the spatial differentiation of O₃ concentration, and the sources of O₃ were analyzed using a backward trajectory model and emission inventory construction. The results showed that the daily and monthly variation in O₃ concentration in the Guanzhong Region were unimodal. The daily maximum value appeared at 15：00, the minimum value appeared at 07：00, the peak value of the monthly average appeared in June, and the valley value appeared in December. The O₃ concentration was highest in summer, followed by that in spring, and the lowest in winter. The days of O₃ exceeding the standard showed mainly mild pollution, and moderate and above pollution showed a trend of decreasing first and then increasing. The O₃ concentration in the Guanzhong Region was mainly closely related to precursors and meteorological factors, and the explanatory power of the interaction of each factor was significantly greater than that of any single factor. The regional transport of O₃ concentration in the Guanzhong Region was mainly affected by easterly airflow, followed by the northwest direction, with the potential source areas located mainly in Henan Province and Hubei Province. The main local sources of volatile organic compounds （VOCs） were solvent use sources, process sources, and mobile sources, and the main emission sources of nitrogen oxides （NO_x） were mobile sources and industrial production combustion sources. The research results have a guiding significance for O₃ joint prevention and control in the Guanzhong Region.