青岛市降尘中水溶性离子的特征及来源分析

为识别青岛市大气降尘中水溶性离子的空间分布特征和来源,于2017年3月,在青岛市主城区采集了93个降尘样品。分析了水溶性离子NO₃-、Ca2+、SO₄2-、Cl-、Na+、K+、Mg2+、NH₄+含量,研究了空间分布和来源。结果表明:NO₃-、Ca2+、SO₄2-是青岛市降尘中的主要水溶性离子,占总水溶性离子质量浓度的82%;离子间的空间分布存在差异,离子浓度较高区域主要集中于市南、市北的西南部,以及崂山区东北部,主要受城区人为排放影响;4个市区NO₃-/SO₄2-质量浓度比值均>1,说明以移动污染源为主;相关性分析及PCA-MLR分析表明,交通源为青岛市降尘中的水溶性离子主要来源,其次是土壤扬尘和海盐源。

CHARACTERISTICS AND SOURCES APPORTIONMENT OF WATER-SOLUBLE IONS IN DUSTFALL IN QINGDAO

In March 2017, 93 dustfall samples were collected in the main urban area of Qingdao, with the purpose of understanding the spatial distribution and source of water-soluble ions in the atmospheric dustfall in Qingdao. The contents of water-soluble ions were determined, including NO₃-, Ca2+, SO₄2-, Cl-, Na+, K+, Mg2+, NH₄+, and their spatial distribution and source were analyzed. NO₃-, Ca2+ and SO₄2- were the main ions for dust reduction in Qingdao, accounting for 82% of the total mass concentration of water-soluble ions. There were differences in the spatial distribution of ions, and the areas with higher ion concentration were mainly concentrated in the Southwest of Shinan District and Shinbei District, and northeast of Laoshan District, which were mainly affected by human emission. The mass concentration ratio of NO₃-/SO₄2- in the four urban areas was higher than 1, indicating that mobile pollution sources were the main source. Correlation analysis and PCA-MLR analysis showed that the traffic source was the main source of water-soluble ions in dust in Qingdao, followed by soil dust and sea salt.