东北亚冬季PM2.5水溶性离子空间分布特征及来源

为探讨东北亚冬季PM_2.5水溶性离子空间分布特征及来源，测定了2017~2018年沈阳冬季PM_2.5水溶性离子浓度.结果显示：沈阳冬季PM_2.5水溶性离子平均质量浓度为28.5±11.9μg/m³，二次离子（SO₄^2-、NO₃^-和NH₄⁺）的浓度最高，分别占总水溶性离子质量浓度的31.0%、22.4%和19.2%.运用离子化学计量学关系、相关性和主成分分析，探讨了沈阳冬季PM_2.5水溶性离子的可能来源.并整合了东北亚冬季（中国东北、韩国、日本）近20a来PM_2.5水溶性离子数据，发现沿着东亚冬季风，东北亚冬季PM_2.5水溶性离子浓度从中国东北，经韩国海岸、韩国和济州岛，日本海岸至日本整体呈下降趋势，在韩国和日本出现局部上升，且在不同区域，不同水溶性离子占比明显不同.其中，韩国冬季PM_2.5中SO₄^2-、Ca²⁺和K⁺受外来源影响显著，NO₃^-和NH₄⁺主要来自本地源，Cl^-、Na⁺和Mg²⁺主要来自本地源或海源；日本中部冬季PM_2.5中SO₄^2-、NO₃^-、NH₄⁺和K⁺主要来自本地源，Cl^-、Ca²⁺、Na⁺和Mg²⁺主要来自本地源或海源.

Winter spatial distribution and source apportionment of water-soluble ions in PM2.5, Northeast Asia

To explore the spatial distribution and sources of water-soluble ions in winter PM_2.5 of Northeast Asia, we determined the concentrations of PM_2.5 water-soluble ions in Shenyang during winter of 2017~2018. The concentrations of the total water-soluble ions in winter PM_2.5 of Shenyang was (28.5±11.9) µg/m³, and the concentrations of secondary ions (SO₄^2-、NO₃^-、NH₄⁺) were the highest, accounting for 31.0%, 22.4% and 19.2% of total water-soluble ions in mass fraction. We investigated the sources of winter PM_2.5 water-soluble ions in Shenyang by the ion stoichiometry, correlation analysis of water-soluble ions and primary component analysis. By combining our results with previously reported data in Northeast Asia region (northeast China, South Korea and Japan) in recent 20years, we found a downwind decreasing pattern in concentrations of winter PM_2.5 water-soluble ions from the northeast China, through the South Korea, coastal South Korea and Jeju Island, and the coast of Japan to Japan except some peaks at stations near densely populated areas (e.g., South Korea and Japan). Water-soluble ions showed significant regional differences in percentage of mass fraction in the total water-soluble ions in PM_2.5. In the winter PM_2.5 of South Korea, SO₄^2-, Ca²⁺ and K⁺ were significantly affected by external sources. NO₃^- and NH₄⁺ were mainly from local sources, while Cl^-, Na⁺ and Mg²⁺ were dominantly sourced from local sources or sea salt. In Central Japan, SO₄^2-, NO₃^-, NH₄⁺, Ca²⁺ and K⁺ were originated from local sources, while Cl^-, Na⁺ and Mg²⁺ were dominantly sourced from local sources or sea salt.