title: Long-range atmospheric transport of polycyclic aromatic hydrocarbons: a global 3-D model analysis including evaluation of Arctic sources.
abstract: We use the global 3-D chemical transport model GEOS-Chem to simulate long-range atmospheric transport of polycyclic aromatic hydrocarbons (PAHs). To evaluate the model's ability to simulate PAHs with different volatilities, we conduct analyses for phenanthrene (PHE), pyrene (PYR), and benzo[a]pyrene (BaP). GEOS-Chem captures observed seasonal trends with no statistically significant difference between simulated and measured mean annual concentrations. GEOS-Chem also captures variability in observed concentrations at nonurban sites (r = 0.64, 0.72, and 0.74, for PHE, PYR, and BaP). Sensitivity simulations suggest snow/ice scavenging is important for gas-phase PAHs, and on-particle oxidation and temperature-dependency of gas-particle partitioning have greater effects on transport than irreversible partitioning or increased particle concentrations. GEOS-Chem estimates mean atmospheric lifetimes of <1 day for all three PAHs. Though corresponding half-lives are lower than the 2-day screening criterion for international policy action, we simulate concentrations at the high-Arctic station of Spitsbergen within four times observed concentrations with strong correlation (r = 0.70, 0.68, and 0.70 for PHE, PYR, and BaP). European and Russian emissions combined account for ~80% of episodic high-concentration events at Spitsbergen.
authors.affiliation: Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States. clf@mit.edu
authors.forename: Carey L
authors.initials: CL
authors.lastname: Friedman
authors.forename: Noelle E
authors.initials: NE
authors.lastname: Selin
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001110:Arctic Regions; D001272:Atmosphere / Q000032:analysis*; D001564:Benzo(a)pyrene / Q000032:analysis; D003198:Computer Simulation; D004784:Environmental Monitoring; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010616:Phenanthrenes / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D011721:Pyrenes / Q000032:analysis; D012621:Seasons; D014835:Volatilization
chemical_list: D000393:Air Pollutants; D010616:Phenanthrenes; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; D001564:Benzo(a)pyrene; C031181:phenanthrene; C030984:pyrene