| 摘要: |
| 气溶胶中的铁(Fe)是参与生物地球化学循环的重要因子之一, 不仅可以通过大气沉降影响海洋初级生产力, 还对大气环境和人体健康产生重要影响。这些作用在很大程度上依赖于铁的溶解度(%Fes)。尽管粒径是影响气溶胶%Fes的关键因素, 但对%Fes的粒径分布特征研究仍然不足。因此本研究中选择在亚洲大陆气溶胶向西北太平洋传输的重要通道上的沿海城市青岛, 收集了在清洁及污染条件下的PM2.5和PM10样品, 并进一步获取了样品中总铁(FeT)和溶解铁(Fes)的质量浓度及%Fes。结果表明, PM2.5中FeT平均质量浓度为(876.5±604.4) ng/m3, Fes平均质量浓度为(65.5±41.3) ng/m3, 平均%Fes为(8.3%±2.9)%; PM10中FeT平均质量浓度为(3 063.7±2 753.2) ng/m3, Fes平均质量浓度为(94.4±107.3) ng/m3, 平均%Fes为(2.9%±1.1)%。PM2.5与PM10相比, FeT和Fes的质量浓度更低, 但%Fes更高。PM2.5和PM10中%Fes的差异与Fe的来源和大气酸化过程密切相关。通过富集因子分析发现PM10中Fe主要受到自然源的影响, 而PM2.5中Fe主要受人为活动的影响。电镜单颗粒分析发现, 人为活动排放的纳米级富铁颗粒主要集中在细颗粒物, 平均粒径为(337±202) nm; 自然源排放的矿物颗粒具有更大的粒径(1 384±803) nm。无论是清洁还是污染条件下, PM2.5和PM10的%Fes均随酸化程度增大而提高, 且PM2.5中Fe的酸化程度大于PM10。 |
| 关键词: 气溶胶铁 铁溶解度 粒径特征 酸化程度 |
| DOI：10.11759/hykx20250318001 |
| 分类号:X513 |
| 基金项目:国家重点研发计划(2024YFC2815800) |
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| Distribution characteristics of iron solubility in fine particulate matter (PM2.5 and PM10) from northern coastal cities |
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Chen yiqi1, Wei Zheng2, Shen Hengmei2, Yu qingxun1, Yuan qi1
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1.Key Laboratory of Marine Environment and Ecology, Ministry of Education of China, Ocean University of China, Qingdao 266100, China;2.Shandong Provincial Eco-environment Monitoring Center, Jinan 250101, China
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| Abstract: |
| Aerosol Fe is a critical component in biogeochemical cycles, simultaneously influencing oceanic primary productivity via atmospheric deposition and significantly impacting air quality and human health. These effects are largely governed by Fe solubility (%Fes). Although particle size is a critical factor influencing aerosol %Fes, the size-dependent distribution characteristics of %Fesremain poorly understood. Therefore, we collected fine particulate matter 2.5 (PM2.5) and 10 (PM10) samples under clean and polluted conditions in Qingdao, a coastal city located along a major aerosol-transport pathway from the Asian continent to the northwestern Pacific. Thereafter, we determined the mass concentrations of total Fe (FeT), dissolved Fe (Fes), and the resulting %Fes in the samples. The results showed that PM2.5 exhibited FeT and Fes mass concentrations of 876.5±604.4 ng/m3 and 65.5±41.3 ng/m3, respectively, with an average %Fes of 8.3%±2.9%. Conversely, PM10 exhibited higher FeT (3063.7±2753.2 ng/m3) and Fes (94.4±107.3 ng/m3), but a lower %Fes (2.9%±1.1%). The variation in %Fes between PM2.5 and PM10 is closely linked to Fe sources and atmospheric acidification processes. Enrichment factor analysis revealed that Fe in PM10 was mainly from natural sources, whereas Fe in PM2.5 was primarily dominated by anthropogenic activities. Single-particle electron microscopy revealed that anthropogenic Fe-rich nanoparticles were mainly concentrated in the fine PM fraction, with an average size of 337±202 nm. Conversely, mineral particles from natural sources exhibited significantly larger average particle sizes (1384±803 nm). Additionally, under clean and polluted conditions, %Fes in PM2.5 and PM10 increased with the acidification degree, which was notably higher in PM2.5 than in PM10. |
| Key words: aerosol iron iron solubility particle-size distribution acidification degree |
