Climate Change and Emissions Impacts on Atmospheric PAH Transport to the Arctic

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• 作者：Carey L. Friedman ; Yanxu Zhang ; Noelle E. Selin
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：January 7, 2014
• 年：2014
• 卷：48
• 期：1
• 页码：429-437
• 全文大小：395K
• ISSN：1520-5851

文摘

We investigate effects of 2000鈥?050 emissions and climate changes on the atmospheric transport of three polycyclic aromatic hydrocarbons (PAHs): phenanthrene (PHE), pyrene (PYR), and benzo[a]pyrene (BaP). We use the GEOS-Chem model coupled to meteorology from a general circulation model and focus on impacts to northern hemisphere midlatitudes and the Arctic. We project declines in anthropogenic emissions (up to 20%) and concentrations (up to 37%), with particle-bound PAHs declining more, and greater declines in midlatitudes versus the Arctic. Climate change causes relatively minor increases in midlatitude concentrations for the more volatile PHE and PYR (up to 4%) and decreases (3%) for particle-bound BaP. In the Arctic, all PAHs decline slightly under future climate (up to 2%). Overall, we observe a small 2050 鈥渃limate penalty鈥?for volatile PAHs and 鈥渃limate benefit鈥?for particle-bound PAHs. The degree of penalty or benefit depends on competition between deposition and surface-to-air fluxes of previously deposited PAHs. Particles and temperature have greater impacts on future transport than oxidants, with particle changes alone accounting for 15% of BaP decline under 2050 emissions. Higher temperatures drive increasing surface-to-air fluxes that cause PHE and PYR climate penalties. Simulations suggest ratios of more-to-less volatile species can be used to diagnose signals of climate versus emissions and that these signals are best observed in the Arctic.