Fig. 6
From: Copper-enriched automotive brake wear particles perturb human alveolar cellular homeostasis
Different vehicle-derived PM types have distinct elemental characteristics, with NAO and ceramic BWPM differentiated by high copper content. 5 different vehicle-derived PM types were collected using a high-volume cascade impactor, after which, the whole particles were digested and analysed via ICP-MS. A Heatmap showing element concentrations with hierarchical clustering, to group elements enriched in each bulk PM type. B A biplot comparing the first two principal components for the bulk PM. NAO and Ceramic are separated along PC2 (circled in red). C A loadings plot showing the top 15% of elements that are contributing to the direction of the PCs for the bulk PM. For example, high iron concentrations are shifting PC1 values higher (as in the case of SemiMxCu), or high copper concentrations are shifting PC2 values higher (as in the case of NAO and ceramic). D Copper concentration in bulk PM demonstrating higher copper concentrations in NAO and ceramic brake-wear PM