Traffic-related magnetic pollution in urban dust from the Xiamen Island, China

Pollution by magnetic particles is a rising environmental issue with possible adverse health effects such as the Alzheimer's disease. Magnetic particles in urban dust originate from traffic-related activities, industrial products and detrital minerals, yet distribution of magnetic particles in cities is poorly known. Here, we measured magnetic properties of surface roadside dust and topsoils by low-frequency magnetic susceptibility (χLF), saturation isothermal remanent magnetization (SIRM), anhysteretic remanent magnetization (χARM) and advanced rock-magnetic methods. Results show that χLF, SIRM and χARM of roadside dust are much higher than topsoil values. Roadside dusts had much lower percent frequency-dependent susceptibility of 1.83 ± 0.12% than topsoil of 2.96 ± 0.14%. Findings also demonstrate a minor contribution of fine pedogenic grains to the elevated χLF. The high values of dust χLF, SIRM and χARM are explained by the contribution of local, exogenous magnetite-like materials.