Multiphase Chemistry of Reactive Oxygen Species and Free Radicals in Secondary Organic Aerosols

该项目由美国国家科学基金会化学部环境化学科学项目资助。白井和他的研究生和博士后研究员研究大气中的细颗粒物，或称气溶胶。有机颗粒是这些气溶胶的主要成分。这些颗粒物会影响气候、空气质量和公众健康。活性氧物种(ROS)包括羟基(OH)和有机自由基，在大气中有机化合物发生的化学变化中起着核心作用。ROS在云滴中的量化很差，它们在水化学中的作用也没有得到很好的描述。这在评估气溶胶对空气质量的影响方面造成了主要的不确定性。白川方明教授为当地高中教师组织了一年一度的教育研讨会。本次教育研讨会由三个主要活动组成：研讨会、AirUCI实验室之旅和动手实验。在他的研究小组的帮助下，高中教师操作仪器来测量各种样品中包含的自由基，如大气颗粒物、柴油废气颗粒物和烟灰。这项研究项目通过更好地了解我们的环境及其如何影响人类健康，促进了国家的健康和繁荣。该项目研究大气中有机化合物形成ROS的化学机制。有机颗粒在反应室中产生。也可以使用粒子撞击器收集周围的粒子。有机颗粒中的ROS主要使用电子顺磁共振光谱和自旋捕获技术来定量。建立了化学动力学模型，并将其应用于数据分析和解释。该项目的目标是促进对大气水中ROS多相化学的基本理解。该项目包括对本科生、研究生和博士后的指导。为当地高中教师组织了一年一度的环境基本化学教育研讨会。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project is funded by the Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation. Professor Shiraiwa, his graduate student and postdoctoral fellow investigate atmospheric fine particulate matter, or aerosols. Organic particles are a major component of these aerosols. These particles influence climate, air quality and public health. Reactive oxygen species (ROS) including hydroxyl (OH) and organic radicals play a central role in the chemical changes that take place in organic compounds in the atmosphere. ROS are poorly quantified in cloud droplets and their role in aqueous chemistry is poorly characterized. This causes major uncertainties in evaluating aerosol effects on air quality. Professor Shiraiwa organizes an annual educational seminar for local high school teachers. This educational seminar consists of three major activities: seminar, AirUCI lab tour, and hands-on experiments. With help from his research group, high school teachers operate instrumentation to measure free radicals contained in a variety of samples such as atmospheric particles, diesel exhaust particles, and tobacco ash. This research project advances the national health and prosperity by developing a better understanding of our environment and how it can influence human health. The project studies the chemical mechanism of ROS formation from atmospheric organic compounds. Organic particles are generated in a reaction chamber. Ambient particles are also collected using a particle impactor. ROS in organic particles are quantified mainly using electron paramagnetic resonance spectroscopy with a spin trapping technique. A chemical kinetic model is developed and applied for data analysis and interpretation. The project goal is to advance the fundamental understanding of multiphase chemistry of ROS in atmospheric water. The project involves mentoring of undergraduate, graduate, and postdoctoral students. An annual educational seminar on environmental radical chemistry is organized for local high school teachers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.