Magnetic Properties of Air Polluting Suspended Particles Deposited on the Leaves of Platanus Orientalis to Monitor Air Pollution in Tehran

Monitoring the magnetic properties of suspended particles in the air deposited on the leaves of trees provides useful information on the spatial distribution of the suspended particles in urban and industrial areas. This study was carried out to extend and develop the application of peripheral magnometry method to investigate environmental pollution and metal contaminants resulted from vehicle traffic in some areas of Tehran with heavy traffic. The leaves of Platanus Orientalis in the inland areas of Chitgar Park as a clean area and Azadi Square and Geisha Bridge as crowded areas were collected. Magnetic components such as natural magnetic residual, mass magnetic susceptibility, isothermal magnetic residual and saturated induction magnetic residual were measured in the samples. The concentration of copper, iron, lead and cadmium was measured by mass spectrometry and the relationship between magnetic components and metals was investigated. The results showed that the highest value of susceptibility and magnetic residual of leaf saturation was associated with heavier traffic of vehicles in Azadi and Geisha. The study of the composition of particles in the Chitgar showed a combination of hard ferromagnetic minerals such as hematite with high concentration and soft ferromagnetic minerals with low concentration, which are the result of the activities of the peripheral industries and traffic in Tehran-Karaj highway. The presence of soft magnetic minerals in both Azadi and Geisha regions was higher than Chitgar. In Azadi, the size of particles was larger and the mineral behavior indicated a combination of the presence of soft and hard minerals, while the size of particle was smaller in Geisha.