Polycyclic aromatic hydrocarbons in bulk deposition at a suburban site: assessment by principal component analysis of the influence of meteorological parameters

Bulk deposition (wet+dry) of 14 polycyclic aromatic hydrocarbons (PAHs) was measured every week from 5 March 2001 to 4 March 2002 on a suburban site at Evreux located 100 km West of Paris (France). Measured concentrations in bulk depositions ranged from 1.1 to 222 ng l−1 with an average of 71.5 ng l−1. The most prevalent PAHs are phenanthrene, fluoranthene and pyrene, which represent 60% of the total concentration on average. The potentially carcinogenic PAHs represent 22% of the PAH concentrations. Statistical analysis, in particular principal component analysis (PCA), allowed us to analyse this data set, highlighting the influence of meteorological parameters (temperature, precipitation amount) on PAH concentration, both quantitatively and qualitatively. The temperature played an important role for PAH concentration in bulk deposition and influenced the efficiency of washout, while rainfall amounts seemed to have a minor influence. Thus, we found seasonal trends in PAH concentration. High rainfall correlated with high proportions of light PAHs. Finally, the study of wind directions allowed us to localize sources of PAHs and to estimate their respective contribution. The influence of the urban area of Rouen on PAH concentrations measured at Evreux is emphasized.