Photodegradation Reactions Mono and Dinitro PAHs

单硝基多环芳烃和二硝基多环芳烃光降解反应

• 批准号: 7676086
• 负责人: RAFAEL ARCE
• 金额: $ 25.64万
• 依托单位: UNIVERSITY OF PUERTO RICO RIO PIEDRAS
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7676086
• 关键词: 1-Nitropyrene; 2,4-Dinitrophenol; Aerosols; Affect; Air; Air Pollutants; Air Pollution; Area; Aromatic Polycyclic Hydrocarbons; Automobile Exhaust; Benzo(a)pyrene; Biological Assay; Breathing; Caliber; Carbon; Cardiopulmonary; Cardiovascular system; Chemicals; Classification; Coal; Complex; DNA Sequence Rearrangement; Data; Death Rate; Diesel Exhaust; Dissociation; Environment; Environmental Exposure; Environmental Health; Environmental Risk Factor; Evaluation; Excision; Exposure to; Film; Gases; Genetic Recombination; Goals; Health; Human; Hydrogen; Inorganic Sulfates; Kinetics; Knowledge; Laboratories; Lasers; Link; Liquid substance; Lung; Malignant neoplasm of lung; Mechanics; Modeling; Mono-S; Motor Vehicles; Movement; Nature; Nitrites; Oxides; Oxygen; Parents; Particulate; Particulate Matter; Photochemistry; Power Plants; Process; Property; Reaction; Relative (related person); Reporting; Research; Research Personnel; Risk; Risk Assessment; Route; Salts; Smoke; Solid; Solutions; Solvents; Source; Structure; Surface; Surface Properties; System; Techniques; Temperature; Testing; Time; Toxic effect; Triplet Multiple Birth; Unspecified or Sulfate Ion Sulfates; Water; Wood material; Work; base; chemical property; design; fly ash; irradiation; mortality; particle; physical property; physical state; planetary Atmosphere; pollutant; quantum; residence; respiratory; triplet state

DESCRIPTION (provided by applicant): Particulate matter (PM2.5) has been linked to a range of serious respiratory and cardiovascular health problems. The nitroPAHs found in the (PM2.5) are formed during combustion processes or by either chemical or photochemical reactions of polycyclic aromatic hydrocarbon in polluted atmospheres. NitroPAHs have been identified in extracts of respirable particles collected from polluted urban air, diesel exhaust particles, automobile exhaust, coal fly ash and wood smoke. The nitroPAHs are typically less abundant in ambient air than PAHs and are found at concentrations in the range of pg/m3 to ng/m3. Nonetheless, some of them could be more mutagenic or carcinogenic in laboratory bioassays than the parent PAH. Thus, it is of great significance to understand their sources and transformations in the atmosphere in assessing environmental exposure and risks. Specifically, their transformations at the solid/air interface or in the liquid-like environment of the organic fraction of the combustion derived aerosols can have a significant impact on controlling their residence time in the environment. It is important to study the photochemistry in these two environments because their photodegradation can proceed by entirely different mechanisms depending on the reaction medium. We are proposing to utilize techniques, already developed in our laboratory, to study the photochemical transformation mechanisms of nitroPAHs adsorbed or absorbed into models of atmospheric particulate matter in order to provide some understanding of the fate of these contaminants in the atmosphere. As we have found with PAHs, that phototransformations at the solid/air interface can have a significant impact in controlling their residence time in the environment, and are thus important in the evaluation of the potential risks of these contaminants, as well as in the possible design of systems for their removal. The working hypothesis is that the physical and chemical properties of the particulate matter are determining factors in the reactivity of the excited states and intermediates participating in the photochemical transformations of these pollutants in that environment. In order to understand the phototransformation mechanism of adsorbed or absorbed nitroPAHs we will: (1) isolate/and characterize the principal stable photoproducts and determine their quantum yields and the effect of the nature of the solvent (polar, non polar, polar aprotic, hydrogen abstraction easiness), and of organic compounds found in the atmospheric aerosols on the product yields, (2) isolate and characterize the principal stable photoproducts produced on adsorbents that mimic the atmospheric particle matter such as inorganic oxides, and sulfate salts, and determine the effect of the physical and chemical properties of the surfaces of these solids (such as composition average pore diameter, surface coverage) on the products relative yields, and to compare their relative yields and distribution with those obtained in the different solvents. The effect of coadsorbed water and oxygen on the yields will also be examined and (3) identify and characterize the participating excited states and reactive intermediates in the phototransformation process occurring in solution and on the surfaces. Related to this aim is the determination of the effect of organic cosolutes encountered in the atmospheric aerosol on the reaction kinetics of the intermediates. The physical properties of the participating excited states and reactive intermediates will be supported by quantum mechanical calculations.

描述（由申请人提供）：颗粒物（PM2.5）与一系列严重的呼吸和心血管健康问题有关。在燃烧过程中或通过污染大气中多环芳烃的化学或光化学反应形成（PM2.5）中发现的硝化物。在从污染的城市空气，柴油排气颗粒，汽车排气，煤灰和木烟中收集的可呼吸颗粒提取物中已经鉴定出了硝化物。在环境空气中，硝化物通常比PAH少，并且在Pg/m3至Ng/m3的浓度下发现。尽管如此，在实验室生物测定中，其中一些可能比父母PAH更具诱变或致癌性。因此，在评估环境暴露和风险方面，了解它们在大气中的来源和转变非常重要。具体而言，它们在固体/空气界面或燃烧衍生气溶胶的有机分数的液体样环境中的转换可能会对控制其在环境中的停留时间产生重大影响。重要的是在这两个环境中研究光化学，因为它们的光降解可以根据反应介质完全不同的机制进行。 我们提议利用已经在实验室中开发的技术来研究硝化核的光化学转化机制吸附或吸收到大气颗粒物质模型中，以便对大气中这些污染物的命运有所了解。正如我们在PAHS中发现的那样，固体/空气界面处的光转化在控制其在环境中的停留时间可能会产生重大影响，因此对于评估这些污染物的潜在风险以及对其去除系统的可能设计而言很重要。工作假设是，颗粒物的物理和化学特性正在确定激发态反应性和参与这些环境中这些污染物光化学转化的中间体的因素。为了理解吸附或吸收硝化物的光转化机制，我们将：（1）分离株/和表征主稳定光产物，并确定其量子产量，并确定其量子的量子，以及溶剂性质的效果，非极性，极性，极性，液化性的液化性和有机化的象征性（极性，极性，高极），以及有机化的成分（有机），富含有机化的成分（在模仿大气粒子物质（例如无机氧化物和硫酸盐盐）上产生的主要稳定的光产物，并确定这些固体表面的物理和化学特性的影响（例如成分平均孔径，表面覆盖，表面覆盖率）对产物相对产量的相对产量和分布的分布，并与之相比。还将检查共掺杂水和氧对产量的影响，（3）识别和表征参与的激发态和反应性中间体在溶液和表面上发生的光转化过程中的反应性中间体。与此目标相关的是确定大气气溶胶中遇到的有机颜色对中间体反应动力学的影响。参与激发态和反应性中间体的物理特性将由量子机械计算支持。