Polycyclic aromatic hydrocarbons (PAHs), oxy- and nitro-PAHs in ambient air of Arctic town Longyearbyen, Svalbard

Polycyclic aromatic hydrocarbons (PAHs) are not declining in Arctic air despite reductions in their global emissions. In Svalbard, the Longyearbyen coal-fired power plant is considered to be one of the major local source of PAHs. Power plant stack emissions and ambient air samples, collected simultaneously 1 km (UNIS) and 6 km (Adventdalen) transect distance, were analyzed (gaseous and particulate phases separately) for 22 nitro-PAHs, 9 oxy-PAHs and 16 parent PAHs by GC/ECNI/MS and GC-MS/MS. Results confirm low level of PAH emissions (∑16 PAHs = 1.5 µg kg-1 coal) from the power plant. Phenathrene, 9,10-anthraquinone, 9-fluorenone, fluorene, fluoranthene, and pyrene accounted for 85% of the plant emission (not including naphthalene). A dilution effect was observed for the transect ambient air samples, 1.26 ± 0.16 and 0.63 ± 0.14 ng m-3 sum all 47 PAH derivatives for UNIS and Adventdalen, respectively. The PAH profile was homogeneous for these recipient stations with phenathrene and 9-fluorenone being most abundant. Principal component analysis, in combination with PAH diagnostic ratios and literature data on different source-specific markers, confirmed coal combustion, gasoline, and diesel traffic as the predominant sources of PAHs. Secondary atmospheric formation of 9- nitroanthracene and 2+3-nitrofluoranthene was evaluated and concluded. Results also indicate that ambient PAH concentrations were affected by precipitation events, and specific humidity is an essential parameter influencing PAH scavenging from the air. The present study contributes important data which can be utilized to eliminate uncertainties in model predictions that aim to assess the extent and impacts of Arctic atmospheric contaminants. 25