Fundamental Studies of Heterogeneous Processes of Atmospheric Importance

过去的大气化学研究主要关注微量气体物质之间发生的“均质”化学过程。对“非均相”过程的关注要少得多，“非均相”过程被定义为发生在或跨越固体、液体或气体介质边界处的物理和化学过程。然而，越来越多的大气科学家认识到，非均质过程在自然大气和污染大气中发生的化学转化中起着重要作用。最近的一个例子是，在南极春季臭氧耗竭过程中，非均质化学对极地平流层云的冰粒所起的关键作用。该项目将测量气态物质（如二甲硫化物和有机过氧自由基）在包括碳质煤烟物质、硫酸和海盐在内的表面上的质量调节。气体和表面反应产物将通过质谱法和热解吸测定。设计这些实验的目的是为了获得建立对流层化学转化数学模型所需的数据，特别是在气溶胶含量高的地区。

Past research in atmospheric chemistry has been largely concerned with "homogeneous" chemical processes occurring among gaseous substances occurring in trace amounts. Much less attention has been given to "heterogeneous" processes, defined as those physical and chemical processes occurring at, or across, boundaries between the solid, liquid, or gaseous media. There is a growing awareness among atmospheric scientists, however, that the heterogeneous processes play important roles in chemical transformations occurring in both natural and polluted atmospheres. A recent example is the crucial role of heterogeneous chemistry on the ice particles of polar stratospheric clouds in the depletion of springtime Antarctic ozone. This project will measure mass accommodation of gaseous species, such as dimethysulfide and organoperoxy radicals, on surfaces, including carbonaceous soot material, sulfuric acid, and sea salt. Gaseous and surface reaction products will be determined by mass spectrometry and thermal desorption. These experiments are designed to yield data required for developing mathematical models of chemical transformations in the troposphere, especially in regions of high aerosol loadings.