Laboratory Studies of Tropospheric Sulfur Chemistry

大气硫循环一直是一个激烈的主题 多年来，环境科学家一直对它感兴趣， 需要评估生物和生物技术的贡献， 人为硫对酸雨、能见度、 减少和改变气候。 在高度工业化的 美国东部和欧洲大部分地区， 人为硫排放量超过自然排放量约 数量级。 然而，在全球范围内， 硫的排放量被认为大约等于 人为来源。 对生物硫的认识 因此，需要一个周期，以建立一个基线， 哪些人为扰动可以比较。 这项研究计划为期三年， 涉及旨在阐明 控制大气的动力学和反应机制 还原硫化合物的氧化。 直接观察 反应性中间体和相对稳定的产品在“真实的” 强调“时间”是因为只有通过这样的观察， 获得具有独特解释的结果。 的 采用的实验方法包括耦合激光闪光 时间分辨的不稳定反应的光解产物 激光诱导的中间体和最终产物的检测 荧光，原子共振荧光，长光程紫外-可见 吸收或可调谐二极管激光（红外）吸收。 只要有可能，实验将在 温度、压力和气体的大气条件 混合物.

The atmospheric sulfur cycle has been a subject of intense interest to environmental scientists for many years because of the need to assess the contributions of biogenic and anthropogenic sulfur to such problems as acid rain, visibility reduction, and climate modification. In heavily industrialized regions such as the eastern United States and much of Europe, anthropogenic sulfur emissions exceed natural emissions by about an order of magnitude. On a global scale, however, biogenic sulfur emissions are thought to approximately equal those from anthropogenic sources. An understanding of the biogenic sulfur cycle is thus required in order to establish a baseline against which anthropogenic perturbations can be compared. This research program is three years in duration and involves continued laboratory studies aimed at elucidating the kinetics and reaction mechanisms which control the atmospheric oxidation of reduced sulfur compounds. Direct observation of reactive intermediates and relatively stable products in "real time" is emphasized because only through such observations can results with a unique interpretation be obtained. The experimental methods to be employed involve coupling laser flash photolysis production of unstable reactions with time-resolved detection of intermediates and end products by laser induced fluorescence, atomic resonance fluorescence, long path UV-visible absorption, or tunable diode laser (infrared) absorption. Whenever possible, experiments will be carried out under atmospheric conditions of temperature, pressure, and gas composition.