Infrared Interrogation of Atmospheric Aerosols

大气气溶胶的红外询问

• 批准号: 9303058
• 负责人: George Ewing
• 金额: $ 20万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-09-15 至 1996-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9303058&HistoricalAwards=false
• 关键词: Infrared; Interrogation; Atmospheric; Aerosols

9303058 Ewing Aerosols in a variety of sizes, shapes and compositions are found throughout the earth's atmosphere. Some are easily observed as clouds, haze, smog or smoke and they affect weather, climatology and the radiation energy balance. Some are nucleation sites or cloud formation. Others are sources of rich chemistry and photochemistry. With the obvious importance of aerosols, many techniques have been directed toward their study. This research advances the view that an understanding of important atmospheric aerosols will be enhanced by exploring the physical and chemical properties of their surfaces. A versatile analytical technique for this exploration is infrared spectroscopy. While many types of aerosols are amenable to infrared spectroscopic interrogation, salt particles are chosen as examples of the analytical techniques. These particles are of particular relevance. Sea salt aerosols generated over the oceans contribute one of the, if not the, most abundant particulate loads on the global atmosphere. Their composition is transformed by an intricate chemistry. Two methods for producing suspended salt particles in a temperature controlled chamber will be investigated. Since the optical path will be in excess of 100 m, infrared sensitivity allows interrogation of the size, shape and composition of the aerosols as well as molecules stuck to their surfaces. For solid salt aerosols the incorporation of OH- and other ions at the surface as well as water overlayers will be explored. Reactions of NO2 at the surface will also be monitored. Water, OH-, NO2 and other oxides have been targeted for laboratory studies of salt because similar surface chemistry is likely to occur in the atmosphere. Experiments to explore the properties of supported salt particles will also be performed and methods for interrogating surface defect concentrations will be explored. It is suggested that atmospheric chemistry is initiated at these surface defects . For ice particles spectroscopic interrogation will likely be able to characterize their interior structure (e.g. amorphous, ice I, or microporous) as well as their surface properties. It is the surface properties that dictate the type of heterogeneous chemistry that occurs in aerosols, whether in the laboratory or in the atmosphere. Preliminary experiments with both suspended and supported aerosols have already been successful in the laboratory of the Principal Investigator. These successes suggest the practically of the experiments. The infrared spectroscopic interrogation of these laboratory produced aerosols will reveal the feasibility for future experiments on aerosols in the atmosphere.

小行星9303058 在地球的大气层中发现了各种大小、形状和成分的气溶胶。 有些很容易观察到的云，霾，烟雾或烟雾，它们影响天气，气候和辐射能量平衡。 有些是成核点或云的形成。 其他是丰富的化学和光化学的来源。 随着气溶胶的重要性越来越明显，许多技术都致力于气溶胶的研究。 这项研究提出了一种观点，即通过探索其表面的物理和化学性质，将加强对重要大气气溶胶的理解。 红外光谱法是一种多用途的分析技术。 虽然许多类型的气溶胶是服从红外光谱的询问，盐颗粒被选为分析技术的例子。 这些粒子具有特别的相关性。 海洋上空产生的海盐气溶胶是全球大气中最丰富的颗粒物之一。 它们的成分被一种复杂的化学物质所改变。 本文将研究在控温室中产生悬浮盐颗粒的两种方法。 由于光路将超过100米，红外灵敏度允许询问的大小，形状和组成的气溶胶以及分子粘在他们的表面。 对于固体盐气溶胶的OH-和其他离子在表面以及水覆盖层的结合将进行探讨。还将监测NO2在地表的反应。 水、OH-、NO2和其他氧化物一直是盐的实验室研究的目标，因为类似的表面化学可能发生在大气中。 还将进行实验以探索支持盐颗粒的性质，并探索询问表面缺陷浓度的方法。 有人建议，大气化学开始在这些表面缺陷。 对于冰颗粒，光谱询问将可能能够表征其内部结构（例如，无定形、冰I或微孔）以及其表面性质。 无论是在实验室还是在大气中，气溶胶的表面性质决定了气溶胶中发生的非均相化学的类型。 在主要研究员的实验室中，悬浮和支撑气溶胶的初步实验已经取得成功。 这些成功表明了实验的实用性。 这些实验室产生的气溶胶的红外光谱询问将揭示未来的实验在大气中的气溶胶的可行性。