| 摘要: |
| 有机物是大气气溶胶中非常重要的化学组分，对我国空气污染及灰霾事件发生具有显著的贡献，是当前大气化学研究的最前沿课题之一。有机气溶胶中包含大量有毒物质（如多环芳香烃、多氯联苯及有机胺类等），直接危害人体健康。目前气溶胶中有机组分的体内/体外生物毒性研究多集中于污染源直接排放的一次颗粒物，对于大气中二次有机气溶胶的形成和毒性效应的关注很少。本文以多环芳烃、有机胺及自然源萜烯类挥发性有机物为例，简要综述了大气中二次有机气溶胶的形成及其生物毒性效应，重点关注这些二次有机气溶胶的形成对母体有机组分生物毒性的增强作用，以增进对大气气溶胶污染的健康危害认识。 |
| 关键词: 二次有机气溶胶 毒性 多环芳烃 有机胺 萜烯 |
| DOI：10.7515/JEE201605001 |
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| 基金项目:中国科学院战略先导性专项（XDB05000000） |
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| Formation and toxicological effect of secondary organic aerosols |
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CAO Junji, LI Jianjun1,2,3
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1. Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China;2. Key Laboratory of Aerosol Chemistry and Physics, Chinese Academy of Sciences, Xi’an 710061, China;3. State Key Laboratory of Loess and Quaternary Geology, Xi’an 710061, China
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| Abstract: |
| Background, aim, and scope Along with the rapid development of Chinese economy, pollutants derived from increasing usage of fossil fuels and biofuels, as well as emissions from waste incineration and dust have been causing serious air pollution problems in many areas of China. Particular matter (PM), especially anthropogenic aerosols, emitted from various sources may alter regional atmospheric stability, and are of significant impact on climate change and human health. Comparing with PM10 (aerodynamic diameter ≤10 μm), fine particle (PM2.5, aerodynamic diameter ≤2.5 μm) do more damage to human health. Organic matter (OM), an important chemical composition of fine particle, takes 20%—90% of the fine particles, has a significant impact on air pollution and haze event which is happening in China, and has become a frontier of atmospheric chemistry research area. Consisting with many toxic compounds, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organic amines and so on, organic aerosol is harmful for human health. Many in-vitro and in-vito studies of biological toxicity were focused on the primary particulate matters emitted directly from the pollution sources, however, attention for the formation and toxicity of secondary organic aerosols (SOA) are really scarce and therefore urgent. Materials and methods Taking PAHs, amines, and biogenic terpenes as examples, in order to improve the understanding on health damage of SOA pollution, this article briefly reviewed the formation and bio-toxicity effects of specific group of SOA, and focused on the rising toxicity of the products comparing with their parent compounds. Results (1) Polycyclic aromatic hydrocarbons (PAHs). Because of the mutagenic, teratogenic and carcinogenic properties, PAHs has focused a great deal of attention from scientific researchers and is considered as one of the most important organic pollutants in the atmosphere. Parent PAHs in the aerosols can undergo a photo-oxidation or nitration reaction with gas oxidants in the air to form oxygenated-PAHs (OPAHs) or nitrated-PAHs (NPAHs), and thus the toxicity and health hazard are enhanced. Parent PAHs and their derivatives can absorb light energy to reach the photo-excited states, and then react with molecular oxygen, medium, and coexisting chemicals to produce reactive oxygen species (ROS) and other reactive intermediates, which can induce lipid peroxidation and DNA damage. (2) Amine: Organic amines are derivatives of ammonia in which one or more of the hydrogen atoms replaced by an alkyl or aryl group. They are strong alkaline compounds and play a very important role on secondary aerosols formation. The gaseous aliphatic amines can undergo rapid acid-base reactions to form salt particles in the presence of atmospheric acids (such as HCl, HNO3, H2SO4). Other multiphase reactions of amines include carbonyl-amine interaction and particle-phase oxidation reactions. Particulate alkyl amine can also react with nitrite to form carcinogenic nitrosamine. All these secondary products have significantly adverse effects on human health, such as skin allergy, respiratory diseases, and cancers etc., and thus would alter the biological effect of aerosols in the atmosphere in return. (3) Terpenes: Terpenes is one of the most important biogenic volatile organic compounds (BVOCs) in the atmosphere. In indoor environment, terpenes can be easily emitted from many consumer products such as furnitures or clothes. On the other hand, some gaseous oxidants like ozone and NOx can also present in the indoor air because of the infiltration from outdoor environment or emission by some office and consumer equipment. Thus, the indoor health effect of secondary organic aerosol formation of terpenes with other gaseous oxidants is a popular issue in recent researches. Some of the gaseous products formed are irritating to biological tissues, while the condensed-phase products have received attention due to their contribution to ambient fine particulate matter and its respective health significance. Although the biochemical mechanism of terpenes to human body remains unclear, but nearly all the related studies can prove that the secondary products of terpenes have some harmful effect to human epidermis or respiratory system. Discussion At present, many researches were focused on the bio-toxicity effects of fine particles in the atmosphere, however, rare studies referred to the toxicity change of secondary organic aerosols formation in the atmosphere. Conclusions More specific areas in which improvements and advances could be made for toxicological studies of secondary organic aerosols in the atmosphere in the future. Recommendations and perspectives (1) Comprehensive study combining the chemical and bio-toxicity properties of secondary organic aerosols; (2) Research on bio-toxicity of secondary organic aerosols from specific pollution sources. |
| Key words: secondary organic aerosols (SOA) toxicity polycyclic aromatic hydrocarbons (PAHs) amines terpenes |
