Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720;
Department of Chemistry, University of California, Riverside, CA 92521.
Proc Natl Acad Sci U S A. 2018 Feb 27;115(9):2038-2043. doi: 10.1073/pnas.1717513115. Epub 2018 Feb 12.
The chemical complexity of atmospheric organic aerosol (OA) has caused substantial uncertainties in understanding its origins and environmental impacts. Here, we provide constraints on OA origins through compositional characterization with molecular-level details. Our results suggest that secondary OA (SOA) from monoterpene oxidation accounts for approximately half of summertime fine OA in Centreville, AL, a forested area in the southeastern United States influenced by anthropogenic pollution. We find that different chemical processes involving nitrogen oxides, during days and nights, play a central role in determining the mass of monoterpene SOA produced. These findings elucidate the strong anthropogenic-biogenic interaction affecting ambient aerosol in the southeastern United States and point out the importance of reducing anthropogenic emissions, especially under a changing climate, where biogenic emissions will likely keep increasing.
大气有机气溶胶（OA）的化学复杂性导致其来源和环境影响的理解存在很大的不确定性。在这里，我们通过具有分子水平细节的成分特征来限制 OA 的来源。我们的结果表明，美国东南部受人为污染影响的森林地区阿拉巴马州森特维尔夏季细 OA 中，有大约一半来自单萜烯氧化的二次有机气溶胶（SOA）。我们发现，涉及氮氧化物的不同化学过程在白天和夜间在决定单萜烯 SOA 的产生量方面起着核心作用。这些发现阐明了影响美国东南部环境气溶胶的强烈人为-生物相互作用，并指出减少人为排放的重要性，特别是在气候变化下，生物排放可能会继续增加。
