Non long‐range corrected density functionals incorrectly describe the intensity of the CH stretching band in polycyclic aromatic hydrocarbons

Author(s):  
Hugo Geindre ◽  
Abdul‐Rahman Allouche ◽  
Daniel Peláez
2010 ◽  
Vol 7 (6) ◽  
pp. 504 ◽  
Author(s):  
Petr Kukučka ◽  
Gerhard Lammel ◽  
Alice Dvorská ◽  
Jana Klánová ◽  
Andrea Möller ◽  
...  

Environmental context Is long-range transport from populated and industrialised areas to blame for pollution of remote regions? We report that, for the world's most remote region, Antarctica, and one prominent class of global pollutants, polycyclic aromatic hydrocarbons, long-range transport from other continents has not contributed significantly to recent snow contamination. Rather, the major sources are regional scientific stations and ocean transport, mostly tourism. Abstract Firn samples attributed to the period between 2002 and 2005 were collected from a snow pit on the Ekström Shelf Ice in the Weddell Sea (70°43.8′S, 8°25.1′W). Low-volume meltwater samples (5 mL) were extracted by solid-phase microextraction (SPME) and analysed for polycyclic aromatic hydrocarbons (PAHs) by gas chromatography-mass spectrometry. The recovery of the analytical method for the 4–6 ring PAHs was low. PAH concentrations in snow were found within the range of 26–197 ng L–1. The most prevailing substances were determined to be naphthalene, 1- and 2-methylnaphthalene, acenaphthylene, acenaphthene and phenanthrene, with naphthalene accounting for an overall mean of 82% of total PAH. Potential emission sources of PAHs in snow were studied using back-trajectory statistics and available emission data of combustion sources in and around Antarctica. The distance to the sources (ships and research stations) in this region was found to control the snow PAH concentrations. There was no indication for intercontinental transport or marine sources.


2019 ◽  
Vol 19 (6) ◽  
pp. 1252-1258 ◽  
Author(s):  
Kazuichi Hayakawa ◽  
Ning Tang ◽  
Edward G. Nagato ◽  
Akira Toriba ◽  
Kazuma Aoki

Author(s):  
Kazuichi Hayakawa ◽  
Ning Tang ◽  
Wanli Xing ◽  
Pham Kim Oanh ◽  
Akinori Hara ◽  
...  

PM2.5 and PM>2.5 were separately collected in Kanazawa, Japan in every season from the spring of 2017 to the winter of 2018, and nine polycyclic aromatic hydrocarbons (PAHs) and six nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by HPLC with fluorescence and chemiluminescence detections, respectively. Atmospheric concentrations of both PAHs and NPAHs showed seasonal changes (highest in the winter and lowest in the summer), which were different from the variations of TSP and PM2.5 (highest in the spring). Contributions of major sources to combustion-derived particulate (Pc) in PM2.5 were calculated by the NP-method using pyrene and 1-nitropyrene as representative markers of PAHs and NPAHs, respectively. The annual average concentration of Pc accounted for only 2.1% of PM2.5, but showed the same seasonal variation as PAHs. The sources of Pc were automobiles (31%) and coal heating facilities/industries (69%). The source of Pyr was almost entirely coal heating facilities/industries (98%). A backward trajectory analysis showed that automobile-derived Pc was mainly from Kanazawa and its surroundings and that coal heating facilities-derived Pc was transported from city areas in central and northern China in the winter and during the Asian dust event in the spring. These results show that large amounts of PAHs were long-range transported from China in the winter. Even in spring when the coal heating season was over in China, PAHs came over to Japan after Asian dust storms passed through Chinese city areas. The main contributor of NPAHs was automobiles in Kanazawa and its surroundings. The recent Pc concentrations were much lower than those in 1999. This decrease was mostly attributed to the decrease in the contribution of automobiles. Thus, changes of atmospheric concentrations of Pc, PAHs and NPAHs in Kanazawa were strongly affected not only by the local emissions but also long-range transport from China.


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