International Research Fellowship Program: Analysis of Mexico City Air Pollution Using Nitrogen and Sulfur Dioxide Column Density Measurements From UV/visible Spectroscopy

[653087]国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Megan L. Melamed博士与Michel Grutter博士在墨西哥墨西哥城的墨西哥国立自治大学开展为期24个月的研究。特大城市（人口超过1000万的城市）在地方、区域和全球空气污染中发挥着关键作用。主要关注的一个特大城市是墨西哥城，它是世界第三大城市，面积为1500平方公里，人口约为2000万。墨西哥城位于热带地区，海拔2240米，是一个三面环山的平坦盆地。墨西哥城的主要污染源是交通、发电和工业过程。高密度的人口、独特的地理环境和多种排放源导致墨西哥城经常发生高污染事件。主要关注的两种污染物是二氧化硫和二氧化氮，它们参与形成酸雨、对流层臭氧和颗粒的大气过程。本研究解决了在大墨西哥城盆地地区的两个研究地点的二氧化硫和二氧化氮的紫外/可见光谱测量的分析和解释。其中一个研究地点位于墨西哥国立自治大学（UNAM）的墨西哥城盆地。第二个研究地点是Altzomoni，位于墨西哥城盆地东南部，海拔约2000米，高于墨西哥国立自治大学研究地点。对这两个研究地点的二氧化硫和二氧化氮测量结果的分析和解释，为墨西哥城盆地污染的流出和流入以及墨西哥城空气污染羽流的边界层动力学提供了重要信息。除了墨西哥国立大学和阿尔佐莫尼的固定研究点外，正在使用一个移动研究平台来测量来自墨西哥城盆地点源的二氧化硫和二氧化氮的排放通量。固定和移动研究平台的测量结果正在应用于化学输送模型，以便更好地模拟区域和全球尺度上城市污染物的输送和转化。二氧化硫和二氧化氮的测量有助于了解特大城市污染对地方、区域和全球的影响。

0653087MelamedThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Megan L. Melamed to work with Dr. Michel Grutter at Universidad Nacional Autonoma de Mexico in Mexico City, Mexico.Megacities (cities with a population greater than 10 million) play a critical role in local, regional, and global air pollution. One megacity of primary interest is Mexico City, the third largest city in the world with an estimated population of ~20 million within an area of 1,500 square kilometers. Mexico City is located in the tropics at 2,240 meters above sea level in a flat basin surrounded by mountains on three sides. The primary sources of pollution in Mexico City are transportation, electricity generation, and industrial processes. The high-density population, the unique geographical setting, and multiple emission sources lead to high pollution episodes on a regular basis in Mexico City. Two pollutants of primary concern are sulfur dioxide and nitrogen dioxide, which are involved in atmospheric processes that form acid rain, tropospheric ozone, and particles. This research addresses the analysis and interpretation of ultraviolet (UV)/visible spectroscopy measurements of sulfur dioxide and nitrogen dioxide from two research sites in the greater Mexico City basin area. One research site is located in the Mexico City basin at La Universidad Nacional Autonoma de Mexico (UNAM). The second research site is Altzomoni, which is located to the southeast of the Mexico City basin at ~2,000 meters in altitude above the UNAM research site. Analysis and interpretation of the sulfur dioxide and nitrogen dioxide measurements from these two research sites is providing important information in regards to the outflow and in flow of pollution to the Mexico City basin and to the boundary layer dynamics of the Mexico City air pollution plume. In addition to the stationary research sites at UNAM and Altzomoni, a mobile research platform is being used to measure emission fluxes of sulfur dioxide and nitrogen dioxide from point sources in the Mexico City basin. The measurements from the stationary and mobile research platforms are being applied to chemical transport models in order to better simulate the transport and transformation of urban pollutants on regional and global scales. The sulfur dioxide and nitrogen dioxide measurements are contributing to the understanding of the impacts of pollution from a megacity on a local, regional, and global level.