“…The PCA indicated the presence of five components in the dataset, each of which explaining at least one unit of variance (Table 3, loadings greater than 0.5 are shown in bold). Each of these factors can be identified as either an emission source, or a chemical interaction (Wu et al, 2013), while their relative contribution reflects differences in emission sources and processes that control the aerosol composition (Putaud et al, 2004).…”