Comprehensive characterization of atmospheric organic carbon at a forested site
Comprehensive characterization of atmospheric organic carbon at a forested site
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DOI：
10.1038/ngeo3018
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发表时间：
2017-10-01
影响因子：
18.3
通讯作者：
Kroll, Jesse H.
中科院分区：
文献类型：
--
作者：
Hunter, James F.;Day, Douglas A.;Kroll, Jesse H.
大气有机化合物是影响空气质量、生态健康和气候的关键化学过程的核心。然而，长期以来在预测有机气溶胶形成和氧化剂寿命等重要数量方面的困难表明，我们对大气有机化学的理解基本上是不完整的，部分原因可能是存在无法使用标准分析技术测量的有机物种。在这里，我们介绍了用五台最先进的质谱仪同时在一个地点(夏季的黄松林)对广泛的大气有机化合物-包括以前未测量的物种-进行的测量。合并的数据集提供了大气有机碳的全面特征，涵盖了广泛的化学性质(挥发性、氧化态和分子大小)，并且没有明显的测量差距。这使得能够首先建立基于测量的当地有机预算，突出这种环境中的高排放、沉积和氧化通量。此外，以前未测量的物种，包括半挥发性和中挥发性有机物种(S/IVOCs)，占总有机碳的三分之一，并且(误差内)提供了OH反应性和潜在的二次有机气溶胶形成的闭合。
Atmospheric organic compounds are central to key chemical processes that influence air quality, ecological health, and climate. However, longstanding diffculties in predicting important quantities such as organic aerosol formation and oxidant lifetimes indicate that our understanding of atmospheric organic chemistry is fundamentally incomplete, probably due in part to the presence of organic species that are unmeasured using standard analytical techniques. Here we present measurements of a wide range of atmospheric organic compounds-including previously unmeasured species-taken concurrently at a single site (a ponderosa pine forest during summertime) by five state-of-the-art mass spectrometric instruments. The combined data set provides a comprehensive characterization of atmospheric organic carbon, covering a wide range in chemical properties (volatility, oxidation state, and molecular size), and exhibiting no obvious measurement gaps. This enables the first construction of a measurement-based local organic budget, highlighting the high emission, deposition, and oxidation fluxes in this environment. Moreover, previously unmeasured species, including semivolatile and intermediate-volatility organic species (S/IVOCs), account for one-third of the total organic carbon, and (within error) provide closure on both OH reactivity and potential secondary organic aerosol formation.