Photochemical Aging of Asian Particulate Matter: Formation of Oxygenated Polycyclic Aromatic Hydrocarbons

该项目正在研究长距离迁移的多环芳烃化合物发生的反应。多环芳烃是由许多类型的燃烧排放的，来自汽车，发电厂和野火等来源。当这些化合物与大气中的臭氧和羟基发生反应时，它们可能会变得更具毒性。 本研究的具体目标包括：1）预测高分子量多环芳烃在光化学氧化过程中可能形成的氧化多环芳烃; 2）利用实验室光化学反应器研究和新的分析方法，测量亚洲颗粒物上氧化多环芳烃产物的形成;以及3）测量从亚洲和太平洋西北部美国实验室收集的粒度分级颗粒物的含氧多环芳烃成分。将使用的方法包括二维气相色谱法和飞行时间质谱法（GCxGC/ToF-MS）用于分析PAH、OPAH级分和羟基-PAH（OH-PAH）级分，和气相色谱-高分辨率质谱（GC/HRMS），以确认化合物的身份。将对以前从中国、日本和韩国采集的样本进行分析，以代表亚洲运输的颗粒物特征。将评估之前从华盛顿和俄勒冈州采集的样本是否受到亚洲运输的影响。将使用混合单粒子拉格朗日综合轨迹（HYSPLIT）4.0模型计算采样气团的四天前后轨迹。气象数据和CO、O3、NO、SO2的浓度以及气溶胶散射将用于帮助解释有关PAH潜在来源的数据。研究结果将有助于更好地了解亚洲颗粒物的光化学老化以及跨太平洋大气输送到美国西海岸期间含氧PAH的潜在形成。

This project is investigating the reactions that occur on polycyclic aromatic hydrocarbon (PAH) compounds that are transported over long distances. PAHs are emitted by many types of combustion, from sources such as automobiles, power plants, and wildfires. When these compounds undergo reactions with ozone and the hydroxyl radical in the atmosphere, they may become more toxic. As PAHs age and are transported over long distances, they may cause an increasing risk to human health.The specific goals of this research include: 1) predicting which oxygenated PAH are likely to form from the photochemical oxidation of higher molecular weight PAHs; 2) measuring the formation of oxygenated PAH products on Asian particulate matter using laboratory photochemical reactor studies and new analytical methods; and 3) measuring the oxygenated PAH composition of size fractionated particulate matter collected from Asia and the Pacific Northwestern U.S. Laboratory methods that will be used include 2D gas chromatography with time-of-flight mass spectrometry (GCxGC/ToF-MS) for analysis of the PAH, the OPAH fraction, and the hydroxy-PAH (OH-PAH) fraction, and gas chromatography with high resolution mass spectrometry (GC/HRMS) to confirm compound identities. Previously acquired samples from China, Japan, and Korea will be analyzed to represent particulate matter characteristic of Asian transport. Previously acquired samples from Washington and Oregon will be assessed for influence from Asian transport. A hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) 4.0 model will be used to calculate four-day forward and back trajectories for air masses sampled. Meteorological data and the concentrations of CO, O3, NO, SO2, and aerosol scattering will be used to aid in the interpretation of the data with respect to potential sources of PAH. The results will lead to a better understanding of the photochemical aging of Asian particulate matter and the potential formation of oxygenated PAH during trans-Pacific atmospheric transport to the U.S. West Coast.