Biomonitoring of air quality in the Cologne conurbation using pine needles as a passive sampler—Part I: magnetic properties

High resolution temporal and spatial control of atmospheric pollutants is of crucial importance for environmental health monitoring. Passive sampling using natural vegetation biomonitoring allows acquisition of well-defined samples at affordable costs. We here present results from a study conducted in the conurbation of Cologne, Germany, based on airborne pollutants accumulated on pine needles. This integrated study includes (i) the microscopic analysis of pine needles and analysis of their magnetic properties, (ii) PAH, and (iii) selected trace elements (Fe, Cd, Pb, Ni, Cr, Cu). A major proportion of atmospheric pollutants is bound to particles, for which in part I of the study we present data on magnetic susceptibility, remanence measurements (IRM, ARM) and total Fe content. SEM-analysis indicates that particles accumulated on needles are mostly