Studies on the physicochemical properties of adsorbed organic adlayers as mimics for atmospheric organic-coated aerosols using fourier transformed infrared spectroscopy

低层大气被称为对流层，由大量被称为气溶胶的微小空气悬浮粒子组成。对流层中的气溶胶具有复杂的化学成分，它们以多种方式影响我们的生活。雾霾天气能见度降低和呼吸健康问题只是区域范围内气溶胶影响的两个例子。在全球范围内，气溶胶影响到达地球表面的太阳光的量，改变云的性质，并为大气中的化学反应提供媒介，从而导致气候变化。通过对气候的计算机模拟，我们能够量化气溶胶对气候变化的贡献程度。然而，气溶胶在这些模拟中的表现仍然不够充分，主要是因为气溶胶的性质复杂，当悬浮在空气中时，它们的反应性和性质随着时间的变化而变化。因此，通过实验研究来解决与气溶胶相关的科学问题，以更好地了解气溶胶对我们气候系统的影响是当务之急。这项提案中要求的资金将用于解决一个重要的科学问题，即气溶胶颗粒的处理和老化，特别是那些包裹着有机物的颗粒。气溶胶中的有机物来自人类活动、自然来源(树木和动物的排放)和生物质燃烧造成的污染。由于反应主要发生在气溶胶表面，为了简化气溶胶复杂的化学性质，我们将使用由真实气溶胶颗粒中识别出的最丰富的化合物组成的模型表面。气溶胶的处理和老化主要是由与大气中发现的污染物气体的反应引起的。我们将使用实验技术，允许在受控制的环境下尽可能接近大气条件的表面上监测反应，以便将结果外推到“真实世界”系统。这些研究取得的成果将增加我们对气溶胶老化过程及其对全球气候的整体影响的理解。

The lower atmosphere, known as the troposphere, comprises a large concentration of minute airborne particles known as aerosols. Aerosols in the troposphere have complex chemical composition and they impact our lives in a number of ways.  Reduced visibility seen on hazy days and respiratory health problems are just two examples of aerosols impact on a regional scale.  On a global scale, aerosols contribute to climate change as they influence the amount of sunlight reaching the Earth's surface, alter properties of clouds, and provide media for chemical reactions in the atmosphere.  Computer simulations of the climate give us the capability of quantifying the magnitude of aerosols contribution to climate change. Yet aerosols representation in these simulations is still inadequate mainly because aerosols are complicated in nature and their reactivity and properties change with time while suspended in air.  Thus, it is imperative to address scientific questions related to aerosols through experimental studies to better our understanding of the aerosols impact on our climate system. The funding requested in this proposal will be used to tackle an important scientific problem, which is the processing and aging of aerosol particles, especially those coated with organic matter.  Organic matter on aerosols originates from pollution stemming from human activity, natural sources (emissions from trees and animals), and biomass burning. Since reactions occur mainly on aerosols surfaces, and in order to simplify the complex chemical nature of aerosols, we will work with model surfaces composed of the most abundant chemical compounds identified in real aerosol particles.  The processing and aging of aerosols are mainly caused by reactions with pollutant gases found in the atmosphere.  We will use experimental techniques that allow monitoring reactions on surfaces under controlled environments as close as possible to atmospheric conditions, so that results can be extrapolated to the "real world" system.  Results obtained from these studies will increase our understanding of the aging process of aerosols and their overall impact on the global climate.