CAREER: Dynamics of Gas-Phase Persistent Organic Chemicals: An Investigation of the Effect of Climate Using a Controlled Chamber

持久性有机化学物质（POPS）从大气中沉积到植物表面可能控制它们的命运和停留时间。持久性有机污染物包括多氯联苯、多环芳烃和有机氯农药，由于这些化合物的亲脂性以及叶子和针叶的蜡状、类脂状表面，它们对植物具有亲和力。由于这种亲和力，植物可能成为大气中持久性有机污染物的汇。植物也可以作为化合物从温暖地区向寒冷地区远距离运输的临时“休息点”。蒸汽相持久性有机污染物是否被植物吸收或释放，预计将取决于化合物、植物和当地气候的特性。理论上，温度和POP的疏水性是蒸汽交换的主要因素。此外，关于环境持久性有机污染物水平的实地数据表明，相对湿度和植物气孔行为也可能起作用。本研究的研究目标是量化局部温度对POP蒸汽-植物表面交换的影响；量化相对湿度对POP蒸汽-植物表面交换的重要性；测定紫外线辐射对植物表面吸收持久性有机污染物的影响。实验将在受控的环境条件下进行，在一个环境室中种植榕树，一种常见的树状室内植物。由于实验室的大小及其再现环境条件的能力，该研究提供了传统实验室浓度与三种气候替代物之间的联系。该试验室为大气模拟、空气污染、云物理和气溶胶研究提供了独特的设施。气候替代物对气相持久性有机化学品与植物表面交换的影响将在本室进行研究。气候替代物包括温度、相对湿度和紫外线辐射。为了测量、模拟和预测低浓度下的动态，将从环境空气中引入气相持久性有机污染物，并通过气流产生柱引入。＊＊＊

9702532 Hornbuckle Deposition of persistent organic chemicals (POPS) from the atmosphere to plant surfaces may control their fate and residence time. POPS, which include polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and organochlorine pesticides have an affinity for plants due to the lipophilic nature of the compounds and the waxy, lipid-like surfaces of leaves and needles. Because of this affinity, plants may act as sinks for atmospheric POPS. Plants may also act a temporary 'resting points' for long-range transport of the compounds from warmer regions to cooler regions of the globe. Whether vapor-phase POPs are taken up or released by plants is expected to depend on characteristics of the compound, the plant, and the local climate. Theoretically, it has been predicted that temperature and POP hydrophobicity should dominate vapor exchange. In addition, field data for ambient levels of POPs has indicated that relative humidity and plant stomatal behavior may also play a role. Research objectives in this study are to quantify the effect of local temperature on POP vapor-plant surface exchange; to quantify the importance of relative humidity on POP vapor-plant surface exchange; to determine to effect of UV radiation on sorption of POPs to plant surfaces. Experiments will be performed under controlled environmental conditions in an environmental chamber populated with Ficus benjamina, a common tree-like house plant. Because of the size of the chamber and its ability to reproduce environmental conditions, the study provides a link between traditional laboratory concentrations as a function of the three climate surrogates. The test chamber provides a unique facility for atmospheric simulation, air pollution, cloud physics, and aerosol research studies. The effect of climate surrogates on exchange of gas-phase persistent organic chemicals with plant surfaces will be examined in this chamber. Climate surrogates include temperature, relative humidity, and ultra violet radiation. Gas phase POPs will be introduced from ambient air, in order to measure, model and predict the dynamics at low concentrations, and introduced via a gas-stream generation column. ***