Reactive oxygen species formed in aqueous mixtures of secondary organic aerosols and mineral dust influencing cloud chemistry and public health in the Anthropocene.
Reactive oxygen species formed in aqueous mixtures of secondary organic aerosols and mineral dust influencing cloud chemistry and public health in the Anthropocene.
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DOI：
10.1039/c7fd00023e
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发表时间：
2017-08
影响因子：
3.4
通讯作者：
Haijie Tong;P. Lakey;Andrea M. Arangio;Joanna Socorro;C. Kampf;T. Berkemeier;W. Brune;U. Pöschl;M. Shiraiwa
中科院分区：
文献类型：
--
作者：
Haijie Tong;P. Lakey;Andrea M. Arangio;Joanna Socorro;C. Kampf;T. Berkemeier;W. Brune;U. Pöschl;M. Shiraiwa
矿物粉尘和二次有机气溶胶(SOA)占大气颗粒物的主要部分，影响气候、空气质量和公众健康。然而，矿物粉尘如何与SOA相互作用来影响云化学和公共健康，目前还不太清楚。在这里，我们应用电子顺磁共振(EPR)光谱，结合自旋捕获技术、LC-MS/MS和动力学模型，研究了大气和生理化学的关键物种--活性氧物种(ROS)在SOA和矿物粉尘混合水溶液中的形成。我们发现，在异戊二烯、α-蒎烯、萘和各种矿物粉尘(沸石、蒙脱石、高岭石、凹凸棒石和撒哈拉尘埃)的水混合物中，可以形成大量的ROS，包括OH、超氧化物以及以碳和氧为中心的有机自由基。总自由基摩尔产率在295K时为∼0.02-0.5%，在310K、254 nm紫外光照射和低pH(<；3)条件下表现出较高的摩尔产率。ROS的形成可以通过与水的相互作用和与溶解的过渡金属离子的Fenton反应来解释有机过氧化氢的分解，有机过氧化氢是SOA的重要组成部分。我们的发现表明，通过与潮解颗粒或云雾小滴中的矿物粉尘相互作用，可以增强SOA颗粒的化学反应能力和老化程度。在低浓度的H_2O_2和Fe~(2+)存在下，SO_2的分解对H_2O_2与Fe~(2+)的经典Fenton反应同样重要，并且可能是水滴中OH自由基的主要来源。在人类呼吸道中，SOA和矿物粉尘的吸入和沉积也可导致ROS的释放，这可能有助于氧化应激，并在人类世大气气溶胶的不利健康影响中发挥重要作用。
Mineral dust and secondary organic aerosols (SOA) account for a major fraction of atmospheric particulate matter, affecting climate, air quality and public health. How mineral dust interacts with SOA to influence cloud chemistry and public health, however, is not well understood. Here, we investigated the formation of reactive oxygen species (ROS), which are key species of atmospheric and physiological chemistry, in aqueous mixtures of SOA and mineral dust by applying electron paramagnetic resonance (EPR) spectrometry in combination with a spin-trapping technique, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a kinetic model. We found that substantial amounts of ROS including OH, superoxide as well as carbon- and oxygen-centred organic radicals can be formed in aqueous mixtures of isoprene, α-pinene, naphthalene SOA and various kinds of mineral dust (ripidolite, montmorillonite, kaolinite, palygorskite, and Saharan dust). The molar yields of total radicals were ∼0.02-0.5% at 295 K, which showed higher values at 310 K, upon 254 nm UV exposure, and under low pH (<3) conditions. ROS formation can be explained by the decomposition of organic hydroperoxides, which are a prominent fraction of SOA, through interactions with water and Fenton-like reactions with dissolved transition metal ions. Our findings imply that the chemical reactivity and aging of SOA particles can be enhanced upon interaction with mineral dust in deliquesced particles or cloud/fog droplets. SOA decomposition could be comparably important to the classical Fenton reaction of H2O2 with Fe2+ and that SOA can be the main source of OH radicals in aqueous droplets at low concentrations of H2O2 and Fe2+. In the human respiratory tract, the inhalation and deposition of SOA and mineral dust can also lead to the release of ROS, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols in the Anthropocene.