State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
Environ Sci Technol. 2020 Jun 16;54(12):7126-7135. doi: 10.1021/acs.est.0c00984. Epub 2020 Jun 3.
Since the implementation of the "Air Pollution Prevention and Control Action Plan" (APPCAP) in 2013, the air quality in China has been greatly improved but still much exceeded the WHO guideline limit. Here we employed a novel approach, two-dimensional Si fingerprints, including stable Si isotopic composition (δSi and Si abundance (Si%), to investigate the annual variations in both primary and secondary sources of PM in Beijing during the APPCAP period (2013-2017). The δSi and Si% values were used as tracers to reflect the variations in primary and secondary sources, respectively. For primary sources, the mean δSi value of PM in 2015-2017 (>-0.5‰) was significantly more positive than that of 2013 (-1.24‰), indicating a dramatic decline in the contribution of Si-depleted sources (i.e., coal burning and industrial emission). For secondary sources, the mean Si% of PM increased from 1.2% in 2013 to 4.6% in 2017, suggesting a large decrease in the secondary aerosol contribution from 83% to 42%. It is worth noting that we found the Si-depleted sources showed a rebound trend during 2015-2017. This study reveals the responses of anthropogenic emission sources under strong regulation policies and provides a reference for future policymaking in Beijing and other polluted regions and countries.
自 2013 年实施《大气污染防治行动计划》（APPCAP）以来，中国的空气质量得到了极大改善，但仍远高于世界卫生组织的指导限值。在这里，我们采用了一种新方法，即二维硅指纹图谱，包括稳定的硅同位素组成（δSi 和 Si 丰度（Si%），来研究北京在 APPCAP 期间（2013-2017 年）PM 的原生和次生来源的年际变化。δSi 和 Si% 值被用作示踪剂，分别反映原生和次生来源的变化。对于原生来源，2015-2017 年 PM 的平均 δSi 值（>-0.5‰）明显比 2013 年的（-1.24‰）更正，表明硅贫化来源（即煤燃烧和工业排放）的贡献急剧下降。对于次生来源，PM 的平均 Si% 从 2013 年的 1.2%增加到 2017 年的 4.6%，表明二次气溶胶的贡献从 83%大幅减少到 42%。值得注意的是，我们发现硅贫化来源在 2015-2017 年呈现出反弹趋势。这项研究揭示了在强有力的调控政策下人为排放源的响应，为北京和其他污染地区和国家未来的政策制定提供了参考。
