Abstract. ∆³-carene is a prominent monoterpene in the atmosphere, contributing significantly to secondary organic aerosol (SOA) formation. However, knowledge about ∆³-carene oxidation pathways, particularly regarding its ability to form highly oxygenated organic molecules (HOM), is still limited. In this study, we present HOM measurements during ∆³-carene ozonolysis under various conditions in two simulation chambers. We identified numerous HOM (monomers: C_7-10H_10-18O_6-14, dimers: C_17-20H_24-34O_6-18) using a chemical ionization mass spectrometer (CIMS). ∆³-carene ozonolysis yielded higher HOM concentrations than α-pinene, with a distinct distribution, indicating differences in formation pathways. All HOM signals decreased considerably at lower temperatures, reducing the estimated molar HOM yield from ~3 % at 20 °C to ~0.5 % at 0 °C. Interestingly, temperature change altered the HOM distribution, increasing the observed dimer-to-monomer ratios from roughly 0.8 at 20 °C to 1.5 at 0 °C. HOM monomers with 6 or 7 O-atoms condensed more efficiently onto particles at colder temperatures, while monomers with nine or more O-atoms and all dimers condensed irreversibly even at 20 °C. Using the gas- and particle-phase chemistry kinetic multilayer model ADCHAM, we were also able to reproduce the experimentally observed HOM composition, yields and temperature dependence.

中文翻译：

---

Δ3-蒈烯臭氧分解产生的高含氧有机分子 (HOM) 的形成及其温度依赖性

摘要。 Δ ³ -蒈烯是大气中一种重要的单萜，对二次有机气溶胶 (SOA) 的形成有显着贡献。然而，关于 Δ ³ -蒈烯氧化途径的知识，特别是关于其形成高氧化有机分子 (HOM) 的能力，仍然有限。在本研究中，我们展示了两个模拟室中不同条件下Δ ³ -蒈烯臭氧分解过程中的 HOM 测量结果。我们使用化学电离质谱仪 (CIMS)鉴定了许多 HOM（单体：C _7-10 H _10-18 O _6-14，二聚体：C _17-20 H _24-34 O _6-18 ）。 Δ ³ -蒈烯臭氧分解产生的 HOM 浓度高于 α-蒎烯，且具有明显的分布，表明形成途径存在差异。所有 HOM 信号在较低温度下显着下降，将估计的 HOM 摩尔产率从 20 °C 时的约 3% 降低到 0 °C 时的约 0.5%。有趣的是，温度变化改变了 HOM 分布，将观察到的二聚体与单体的比率从 20 °C 时的大约 0.8 增加到 0 °C 时的 1.5。具有 6 或 7 个 O 原子的 HOM 单体在较低温度下更有效地缩合到颗粒上，而具有 9 个或更多 O 原子的单体和所有二聚体即使在 20 °C 下也会不可逆地缩合。使用气相和颗粒相化学动力学多层模型 ADCHAM，我们还能够重现实验观察到的 HOM 组成、产率和温度依赖性。