title: Diurnal cycle of PAHs, nitro-PAHs, and oxy-PAHs in a high oxidation capacity marine background atmosphere.
abstract: To improve our understanding of the formation and fate of nitro-PAHs, which contribute to the toxicity of ambient particles, the diurnal variation of their ambient concentration was studied concurrently with the corresponding PAH, OH radical, ozone, and oxy-PAH concentration, during an intensive field campaign at an eastern Mediterranean marine background location (Finokalia, Island of Crete) in August, 2001. The gas-phase PAH and OH radical concentrations maximized at noon. Gas-phase PAH concentrations were correlated (p < 0.001) with ambient temperatures. The gas-phase OH-radical-initiated PAH reaction was identified as the major process contributing to the ambient burden of nitro-PAHs. 2-Nitrofluoranthene and 2-nitropyrene were the most abundant particle-associated nitro-PAHs. A well-defined diurnal pattern was identified for both compounds exhibiting a maximum during midday followed by a rapid decrease. 9,10-Anthracenodione and 9-fluorenone, the most abundant oxy-PAHs, did not present a diurnal variation of concentration.
authors.affiliation: Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71003 Voutes-Heraklion, Greece.
authors.forename: Manolis
authors.initials: M
authors.lastname: Tsapakis
authors.forename: Euripides G
authors.initials: EG
authors.lastname: Stephanou
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D001272:Atmosphere / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D008521:Mediterranean Islands; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons