Soil contains lithogenic components as well as anthropogenic components including combustion residues from traffic activities. The high traffic activities in major cities such as Bandung have caused the air pollution level to increase significantly. These activities might also produce significant combustion residues that accumulate, among others, in the topsoils. Compared with lithogenic components in topsoil, the anthropogenic combustion residues might have different magnetic signatures that could be detected by magnetic measurements. In this study, 38 topsoil samples from 19 roadside sampling points in Bandung City were collected and magnetically analysed to map the magnetic signatures due to traffic activities. The samples were measured for magnetic susceptibility using Bartington MS2B Susceptibility Meter and hysteresis parameter analysed from Vibrating Sample Magnetometer (VSM). The results show that the values of mass-specific magnetic susceptibility (χLF) vary from 391.20 to 1835.20×10-8 m3/kg with the average value of 1012.16 × 10-8 m3/kg while the values of frequency dependent susceptibility (χFD%) vary from 0.54% to 4.48% with the average value of 1.9%. The relatively high value of magnetic susceptibility indicates higher concentration of magnetic minerals compared to that of pristine topsoil around Bandung. This is in agreement with similar studies on roadside topsoil elsewhere. The poor correlation between mass-specific magnetic susceptibility and frequency dependent magnetic susceptibility infers that the magnetic minerals are predominantly non superparamagnetic. This finding is supported by magnetic hysteresis parameters showing that the predominant grains are likely to be pseudo-single domain (PSD) if magnetite is assumed to be the predominant magnetic mineral. Similar studies in German and China reported that the predominant magnetic mineral is mixture of single domain to multi domain magnetite.

High numbers of vehicles and its activity in Bandung City resulting in levels of pollution caused by their particulates on the top soils. Since the urban topsoil containing particulates are harmful, thus its mineralogy and morphology need to identified. The samples of topsoil were taken in several locations around Bandung City. Afterwards, the topsoil samples were extracted for mineralogy and morphology analysis using X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) tests. The result of XRD measurement shows that the magnetic mineral dominated by magnetite. The magnetite is iron rich mineral that could be changed in morphology by the oxidation during environmental changing. Furthermore, the morphology of the magnetic mineral by SEM analysis exhibit the shapes of octahedron and spherules. The octahedron shape represents of paedogenic magnetic mineral carrier while the spherule indicate the presence of anthropogenic mineral. EDX analysis show the evidence of heavy metal elements on the magnetic mineral with spherule shape that caused by vehicles particulates.