Abstract：
A long-term (2013-2019) PM2.5 speciation dataset measured in Tianjin, the largest industrial city in northern China, was analyzed with dispersion normalized positive matrix factorization (DN-PMF). The trends of source apportioned PM2.5 were used to assess the effectiveness of source-specific control policies and measures in support of the two China\'s Clean Air Actions implemented nationwide in 2013-2017 and 2018-2020, respectively. Eight sources were resolved from the DN-PMF analysis: coal combustion (CC), biomass burning (BB), vehicular emissions, dust, steelmaking and galvanizing emissions, a mixed sulfate-rich factor and secondary nitrate. After adjustment for meteorological fluctuations, a substantial improvement in PM2.5 air quality was observed in Tianjin with decreases in PM2.5 at an annual rate of 6.6%/y. PM2.5 from CC decreased by 4.1%/y. The reductions in SO2 concentration, PM2.5 contributed by CC, and sulfate demonstrated the improved control of CC-related emissions and fuel quality. Policies aimed at eliminating winter-heating pollution have had substantial success as shown by reduced heating-related SO2, CC, and sulfate from 2013 to 2019. The two industrial source types showed sharp drops after the 2013 mandated controls went into effect to phaseout outdated iron/steel production and enforce tighter emission standards for these industries. BB reduced significantly by 2016 and remained low due to the no open field burning policy. Vehicular emissions and road/soil dust declined over the Action\'s first phase followed by positive upward trends, showing that further emission controls are needed. Nitrate concentrations remained constant although NOX emissions dropped significantly. The lack of a decrease in nitrate may result from increased ammonia emissions from enhanced vehicular NOX controls. The port and shipping emissions were evident implying their impacts on coastal air quality. These results affirm the effectiveness of the Clean Air Actions in reducing primary anthropogenic emissions. However, further emission reductions are needed to meet global health-based air quality standards.
摘要：
天津市长期(2013-2019年)PM2.5形态测定数据集，中国北方最大的工业城市,采用色散归一化正矩阵分解(DN-PMF)进行分析。利用来源分配的PM2.5趋势评估了分别支持2013-2017年和2018-2020年在全国范围内实施的两项中国清洁空气行动的针对特定来源的控制政策和措施的有效性。DN-PMF分析解决了八个来源：煤燃烧（CC），生物质燃烧，车辆排放,灰尘,炼钢和镀锌排放，富含硫酸盐的混合因子和次级硝酸盐。根据气象波动进行调整后，在天津，PM2.5空气质量大幅改善，PM2.5以6.6%/年的速度下降。CC的PM2.5下降4.1%/年。SO2浓度的降低，CC贡献的PM2.5，和硫酸盐证明了对CC相关排放和燃料质量的改进控制。旨在消除冬季供暖污染的政策取得了实质性的成功，如减少与供暖相关的SO2，CC，和硫酸盐从2013年到2019年。在2013年强制控制措施生效以淘汰过时的钢铁生产并对这些行业实施更严格的排放标准之后，这两种工业来源类型出现了急剧下降。到2016年，生物质燃烧显着减少，由于没有露天燃烧政策，生物质燃烧仍然很低。车辆排放和道路/土壤粉尘在行动第一阶段下降，随后出现积极的上升趋势。表明需要进一步的排放控制。硝酸盐浓度保持恒定，尽管NOX排放量显着下降。硝酸盐缺乏减少可能是由于增强的车辆NOx控制导致的氨排放增加。港口和航运的排放显然意味着它们对沿海空气质量的影响。这些结果肯定了清洁空气行动在减少主要人为排放方面的有效性。然而,需要进一步减少排放，以达到基于健康的全球空气质量标准。
