西北地区河谷城市大气降尘环境磁学特征及其环境意义

应用环境磁学方法对西北地区重点污染城市兰州和清洁对照点黄花滩两地大气降尘的磁学特征进行对比研究,分析了大气降尘磁性矿物含量、类型和颗粒大小等磁学性质及其对城市大气污染的指示意义.结果表明,兰州市大气污染较为严重,大气降尘中磁性矿物含量明显高于黄花滩,且呈现冬季明显高于其他季节的变化趋势.两地降尘样品磁学特征均受磁铁矿控...

Magnetic Property of Dustfall in a Northwest China Valley City and Its Environmental Implications

Lanzhou is one of the seriously polluted cities in Northwest China. Dustfall samples collected in Lanzhou and the countryside Huanghuatan were studied using magnetic methods. The results reveal that the content of magnetic mineral in dustfall samples from Lanzhou is much higher than that of Huanghuatan. At the same time, it has a much higher lever in winter than that of other seasons. The main magnetic minerals in the dustfall from both places are magnetite, maghemite and hematite, and the main magnetic grain sizes in dustfall samples are mainly pseudo single-domain(PSD) and multi-domain(MD). Although the air in Lanzhou is polluted seriously, the air quality has been improved greatly during the past decades and controlled well in recent years. Compared with other cities, air pollution in Lanzhou is affected significantly by urban terrain. This research also reveals that environmental magnetism has become a more and more important method in air pollution study.