Spatial and seasonal variability of atmospheric persistent organic pollutants in northeastern France: passive air...

Persistent and semi-volatile organic contaminants remain important atmospheric tracers because of their environmental persistence, multiple emission pathways and capacity for regional transport. This study investigated the spatial and seasonal variability of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in northeastern France. Nitrogen-doped carbon-coated silicon carbide foam (NMC@SiC) passive air samplers were deployed at six urban, suburban and rural sites in the Strasbourg metropolitan area between 2018 and 2020. Twenty-one OCPs, sixteen PAHs, and twenty-two PCBs were quantified by gas chromatography-tandem mass spectrometry. PAHs exhibited the clearest spatial and seasonal variability, with higher concentrations at urban sites and cold-season or autumn enhancements depending on the location. Naphthalene dominated the PAH profile, while diagnostic ratios suggested dominant combustion inputs, including traffic, residential heating and biomass or solid-fuel burning. PCBs showed weaker spatial contrasts and more homogeneous distributions, with profiles dominated by penta-, hexa- and hepta-chlorinated congeners, indicating diffuse legacy contamination, possible PCB-containing materials, industrially influenced areas and regional redistribution. OCPs were dominated by dichlorodiphenyltrichloroethane-related compounds and hexachlorocyclohexane isomers, reflecting historical residues and secondary volatilization from contaminated environmental reservoirs. These findings highlight the combined influence of current urban emissions, persistent legacy reservoirs, secondary re-emissions and regional atmospheric transport on organic contaminant distributions in northeastern France.