Field Measurements of the Atmospheric Dry Deposition Fluxes and Velocities of Polycyclic Aromatic Hydrocarbons to the Global Oceans

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• 作者：Bel茅n Gonz谩lez-Gaya ; Javier Z煤帽iga-Rival ; Mar铆a-Jos茅 Ojeda ; Bego帽a Jim茅nez ; Jordi Dachs
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：May 20, 2014
• 年：2014
• 卷：48
• 期：10
• 页码：5583-5592
• 全文大小：493K
• 年卷期：v.48,no.10(May 20, 2014)
• ISSN：1520-5851

文摘

The atmospheric dry deposition fluxes of 16 polycyclic aromatic hydrocarbons (PAHs) have been measured, for the first time, in the tropical and subtropical Atlantic, Pacific, and Indian Oceans. Depositional fluxes for fine (0.7鈥?.7 渭m) and coarse (>2.7 渭m) aerosol fractions were simultaneously determined with the suspended aerosol phase concentrations, allowing the determination of PAH deposition velocities (v_D). PAH dry deposition fluxes (F_DD) bound to coarse aerosols were higher than those of fine aerosols for 83% of the measurements. Average F_DD for total (fine + coarse) 危₁₆PAHs (sum of 16 individual PAHs) ranged from 8.33 ng m^鈥?d^鈥? to 52.38 ng m^鈥?d^鈥?. Mean F_DD for coarse aerosol鈥檚 individual PAHs ranged between 0.13 ng m^鈥?d^鈥? (Perylene) and 1.96 ng m^鈥?d^鈥? (Methyl Pyrene), and for the fine aerosol fraction these ranged between 0.06 ng m^鈥?d^鈥? (Dimethyl Pyrene) and 1.25 ng m^鈥?d^鈥? (Methyl Chrysene). The estimated deposition velocities went from the highest mean v_D for Methyl Chrysene (0.17鈥?3.30 cm s^鈥?), followed by Dibenzo(ah)Anthracene (0.29鈥?.38 cm s^鈥?), and other high MW PAHs to minimum values of v_D for Dimethyl Pyrene (<0.04 cm s^鈥?) and Pyrene (<0.06 cm s^鈥?). Dry depositional processes depend on the concentration of PAHs in the suspended aerosol, but also on physicochemical properties and environmental variables (vapor pressure, wind speed, and on the affinity of aerosols for depositing to the sea surface). Empirical parametrizations are proposed to predict the dry depositional velocities of semivolatile organic compounds to the global oceans.