Kinetics and mechanisms of atmospheric hydrocarbon oxidation and particle formation

大气碳氢化合物氧化和颗粒形成的动力学和机制

• 批准号: 106186-2007
• 负责人: Mozurkewich, Michael
• 金额: $ 2.19万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=362062
• 关键词: Kinetics; mechanisms; atmospheric; hydrocarbon; oxidation

Every cubic centimeter of air contains hundreds to over a hundred thousand fine particles with diameters less than one micrometer. These particles can absorb and scatter sunlight and also act as the nuclei on which cloud droplets form. As a result, they play a major role in climate; our incomplete knowledge of how these particles form is a major cause of uncertainty in global climate models. It has also been demonstrated that these particles have a significant negative impact on human health. Fine particles are largely formed by a process called gas-to-particle conversion in which gases, such as sulfur dioxide, aromatic hydrocarbons (from petroleum products) and terpenes (emitted by plants) undergo reactions that convert them to compounds, such as sulfuric acid and oxygenated organic compounds, that form solid and liquid particles.The gas-to-particle conversion process for organic compounds is still only partially understood in spite of a great deal of research. This is due to both the great complexity of these processes and the difficulty of measuring many of the chemical compounds formed in these reactions. The work to be undertaken in this project will be a new approach towards studying these reactions; it is intended that this will add significant new understanding. Normally, the first step in studying systems like these is to isolate and identify the various chemical compounds that are formed. We will instead obtain high time resolution mass spectra of the entire assembly of compounds and use statistical techniques to decompose these into various "components" that each vary in time in a different manner. The idea is that these statistical methods permit the extraction of maximum information from the data. We will then use the methods of chemical kinetics to characterize the time dependencies of the components. This will place the components in a context of chemical reactivity, which will be useful in eventually identifying the chemical compounds that correspond to each component.

每立方厘米的空气中含有数百至十万个直径小于1微米的细颗粒。这些粒子可以吸收和散射阳光，也可以作为云滴形成的核心。因此，它们在气候中发挥着重要作用;我们对这些粒子如何形成的不完整知识是全球气候模型不确定性的主要原因。研究还表明，这些颗粒物对人类健康有显著的负面影响。细颗粒主要是通过一种称为气体到颗粒转化的过程形成的，在该过程中，气体，如二氧化硫、芳香烃（来自石油产品）和萜烯（由植物排放的）经历将它们转化为化合物的反应，例如硫酸和含氧有机化合物，形成固体和液体颗粒。气体-尽管进行了大量的研究，但是对于有机化合物的颗粒转化过程仍然仅仅是部分地了解。这是由于这些过程的高度复杂性和测量这些反应中形成的许多化合物的困难。在这个项目中将要进行的工作将是研究这些反应的一种新方法;这将增加重要的新理解。通常，研究这类系统的第一步是分离和识别形成的各种化合物。相反，我们将获得整个化合物组合的高时间分辨率质谱，并使用统计技术将其分解为各种“组分”，每个组分以不同的方式随时间变化。这个想法是，这些统计方法允许从数据中提取最大的信息。然后，我们将使用化学动力学的方法来表征组分的时间依赖性。这将把组分置于化学反应性的背景下，这将有助于最终识别对应于每个组分的化合物。