Key Laboratory for Urban Habitat Environmental Science and Technology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
Key Laboratory for Urban Habitat Environmental Science and Technology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
Chemosphere. 2019 Dec;236:124383. doi: 10.1016/j.chemosphere.2019.124383. Epub 2019 Jul 17.
The volatility of atmospheric aerosols greatly influences the gas-particle partitioning, chemical mechanisms and lifetime of aerosols. Due to the complex composition, the volatility of organic aerosol is one of the major sources of uncertainty in measuring and modeling ambient aerosols. Despite high aerosol loading in the atmosphere in China, especially in winter, few field measurements were conducted targeting the volatility of ambient organic aerosol (OA). With the deployment of a thermodenuder-aerosol mass spectrometer (TD-AMS) system, the volatility of non-refractory submicron aerosols (NR-PM) were measured on an island near the coastal line for the regional air in wintertime in southern China. NO and Cl showed the highest volatility in the NR-PM chemical species, while SO showed the least volatility. Organic aerosol showed a moderate volatility, evaporating at a stable rate (0.57% °C) at temperatures lower than 150 °C and keeping a stable volatility when its loading increases, which could be an advantage for parameterization of OA in air quality models. Based on both positive matrix factorization and chemical mass balance modeling of OA composition, biomass burning OA was found to be the most volatile factor, followed by hydrocarbon-like OA and more-oxidized oxygenated OA. By summarizing the OA volatility measured in this study and in the literature, we found that the volatilities of different OA factors at different locations do not have a clear relationship with the OA oxidation state, possibly due to the vague understanding of local OA aging mechanisms and mixing states.
大气气溶胶的不稳定性极大地影响了气粒分配、化学机制和气溶胶寿命。由于其复杂的组成，有机气溶胶的不稳定性是测量和建模环境气溶胶时不确定性的主要来源之一。尽管中国大气中的气溶胶负荷很高，尤其是在冬季，但针对环境有机气溶胶（OA）不稳定性的现场测量却很少。通过部署热脱附-气溶胶质谱仪（TD-AMS）系统，在冬季对中国南方沿海地区的一个岛屿上进行了区域空气的非难挥发亚微米气溶胶（NR-PM）的不稳定性测量。NR-PM 化学物质中，NO 和 Cl 具有最高的不挥发性，而 SO 具有最低的不挥发性。有机气溶胶具有中等的不挥发性，在 150°C 以下的温度下以稳定的速率（0.57% °C）蒸发，并且在其负荷增加时保持稳定的不挥发性，这可能是空气质量模型中 OA 参数化的优势。基于 OA 组成的正矩阵因子分析和化学质量平衡建模，发现生物质燃烧 OA 是最易挥发的因素，其次是碳氢化合物样 OA 和更氧化的含氧 OA。通过总结本研究和文献中测量的 OA 不稳定性，我们发现不同地点不同 OA 因素的不稳定性与 OA 氧化状态之间没有明显的关系，这可能是由于对当地 OA 老化机制和混合状态的理解不明确。
