The evolution of atmospheric organic carbon as it undergoes oxidation has a controlling influence on concentrations of key atmospheric species, including particulate matter, ozone and oxidants. However, full characterization of organic carbon over hours to days of atmospheric processing has been stymied by its extreme chemical complexity. Here we study the multigenerational oxidation of α-pinene in the laboratory, characterizing products with several state-of-the-art analytical techniques. Although quantification of some early generation products remains elusive, full carbon closure is achieved (within measurement uncertainty) by the end of the experiments. These results provide new insights into the effects of oxidation on organic carbon properties (volatility, oxidation state and reactivity) and the atmospheric lifecycle of organic carbon. Following an initial period characterized by functionalization reactions and particle growth, fragmentation reactions dominate, forming smaller species. After approximately one day of atmospheric aging, most carbon is sequestered in two long-lived reservoirs—volatile oxidized gases and low-volatility particulate matter.

大气中有机碳的氧化过程对关键的大气物质（包括颗粒物，臭氧和氧化剂）的浓度具有控制性影响。然而，由于其极高的化学复杂性，在数小时至数天的大气处理过程中，有机碳的全部特征受到了阻碍。在这里，我们在实验室中研究α-pine烯的多代氧化，并使用几种最先进的分析技术对产品进行表征。尽管对某些早期产品的量化仍然难以捉摸，但是到实验结束时，就可以实现完全的碳封闭（在测量不确定性范围内）。这些结果为氧化对有机碳特性（挥发性，氧化态和反应性）以及大气中的有机碳生命周期的影响提供了新的见解。在以功能化反应和颗粒生长为特征的初始阶段之后，碎片反应占主导地位，形成了较小的物种。大气老化大约一天后，大部分碳被隔离在两个长寿命的储层中，即挥发性氧化气体和低挥发性颗粒物。