Vapor Absorption of Semivolatile Organic Compounds to Atmospheric Particulate Matter

评估污染物的源、汇、化学和迁移， 有机化合物在对流层，必须定义 几种人造和天然化合物的分布 气相和冷凝相。 目前，数量很少。 关于半挥发性化合物的相分布的可用信息 大气中存在的有机化合物。 蒸汽/粒子 化合物的分布对它们的 大气寿命和它们所经历的化学反应。 半挥发分相分布的直接测量 大气中的化合物是一个具有挑战性的分析问题， 需要更多的研究。 在本项目中， 气相和大气颗粒物之间的化合物（SOC） 物质是通过现场和实验室实验来确定的。 本研究的目的是：（1）确定分区 不同类别半挥发性化合物的行为;（2）测试 假设SOC液相蒸汽压很大程度上 控制对大气中特定物质的吸附;（3）研究 SOC分子形状对吸附的影响; (4)区分“可交换”和“不可交换”SOC， 粒子 在夏季收集大量空气样本， 冬季使用玻璃纤维过滤器备份吸附剂陷阱。 将通过色谱法分析样品。 蒸汽-粒子分配系数由 吸附剂捕集器和过滤器上的SOC浓度以及 悬浮颗粒物浓度 实地和实验室估计 将产生吸附热。 估计 SOC的“不可交换”部分将通过分析过滤器 在用无SOC的空气汽提之后。

To evaluate the sources, sinks, chemistry, and transport of organic compounds in the troposphere, one must define the distribution of several manmade and natural compounds between the gaseous and condensed phases. Currently there is little quantitative information available about the phase distribution of semivolatile organic compounds present in the atmosphere. The vapor/particle distribution of compounds has an important influence on their atmospheric lifetimes and the chemical reactions they undergo. Direct measurement of the phase distribution of semivolatile compounds in the atmosphere is a challenging analytical problem that requires additional research. In this project the distribution of semivolatile organic compounds (SOC) between the vapor phase and atmospheric particulate matter is to be determined through field and laboratory experiments. The objectives of this study are to: (1) determine the partitioning behavior of different classes of semi-volatile compounds; (2) test the hypothesis that the SOC liquid-phase vapor pressure largely controls adsorption to atmospheric particular matter; (3) investigate the influence of SOC molecular shape on adsorption; and (4) distinguish "exchangeable" and "non-exchangeable" SOC on particles. High volume air samples are to be collected in summer and winter using a glass fiber filter backed up by an adsorbent trap. Samples will be analyzed by chromatographic procedures. Vapor-particle partition coefficients are to be calculated from the SOC concentrations on the adsorbent trap and filter and the total suspended particle concentration. Field and laboratory estimates of heats of adsorption will be made. Estimates of the "non-exchangeable" fraction of SOC will be made by analyzing filters after stripping with SOC-free air.