Environmental magnetism: Measuring, monitoring and modelling urban street dust pollution

Abstract

Urban street dusts have been monitored monthly for one year (May 2000 to April 2001), their magnetic properties measured and their multivariate relationships modelled by Simultaneous R- and Q-mode Factor Analysis, so as to differentiate dusts from three urban roads (two in Wolverhampton and one in Dudley) in the West Midlands (U.K.). Results show the street dusts contain a large range of magnetic concentrations, magnetic mineralogy and magnetic domain sizes, which has enabled significant differences (p < 0.001) to be identified between individual roads. Whilst soil is proposed as a notable provenance for the dust, magnetic values in this study are much higher than those previously reported for topsoils and thus, indicate the influence of other sources, such as anthropogenic pollutants. This indicates the potential of magnetic methodologies as a valuable means of contributing to local and national road pollution monitoring schemes. Furthermore, Factor Analysis aided the interpretation of dust variations and simplified the inter-relationships between magnetic parameters, which highlights its potential for classifying and discriminating urban street dust sources.