Aggressive traffic intervention and emission control measures implemented during the 2008 Olympic Games in Beijing created a valuable case study for evaluating the effectiveness of measures for mitigating environmental pollution and protecting public health. Results are reported here for a suite of magnetic and non-magnetic (microscopic, chemical and statistical) methods conducted on street dust deposits and parkland soils around the Olympic Park in Beijing. In both areas magnetic grains with multidomain properties predominate; grain sizes are coarser in the heavy traffic regions and finer in the park areas with evidence for particulate steel dust input in the former case. Traffic is the major source of anthropogenic magnetic particle-induced enhancement of magnetic susceptibility in street dust; however, domestic combustion processes (mainly coal burning) are found to contribute a significant magnetic signature in the urban environment during the winter. Due to the traffic intervention, magnetic compositions in street dust decreases significantly during the Olympic Games. Correlations between magnetic parameters and heavy metal contents prove that magnetic parameters can be used as proxies for heavy metal pollution.