Rapid magnetic biomonitoring and differentiation of atmospheric particulate pollutants at the roadside and around two major industrial sites in the U.K.

Emissions of particulate matter (PM) from vehicle and industrial sources constitute a hazard to human health. Here, we apply biomagnetic monitoring to (a) discriminate between potential PM(10) sources around a steelworks and (b) examine magnetic source differentiation for a combined, U.K.-based, magnetic data set (steelworks, roadside, power-generating site). Tree leaves (sampled September 2009, as passive PM receptors) and putative sources were subjected to rapid magnetic characterization (magnetic remanence measurements). Fuzzy cluster analysis of the combined data set identified three clusters, showing that particulates emitted from vehicle fleets (e.g., diesel/petrol), and from different industrial processes can be magnetically differentiated. Cluster analysis of the steelworks leaf receptors and potential sources identified seven magnetic groupings. Leaves from one PM "hotspot" showed no affinity with any available source sample, suggesting an as yet untested PM source. These data indicate the value of fast, inexpensive magnetic techniques for particulate source discrimination and indication of "missing" sources.