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

9702532持久性有机化学品(持久性有机污染物)从大气到植物表面的霍恩巴克沉积可以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、多环芳香烃和有机氯农药，由于这些化合物的亲脂性以及叶和针叶的蜡状脂类表面，它们对植物具有亲和力。由于这种亲和力，植物可能充当大气持久性有机污染物的汇。植物也可以充当暂时的“休息点”，将化合物从地球上较温暖的地区远距离运输到较凉爽的地区。植物是否吸收或释放气相持久性有机污染物，预计将取决于化合物的特性、植物和当地气候。从理论上讲，温度和POP的疏水性应该是蒸汽交换的主导因素。此外，环境POPs水平的现场数据表明，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地温度对POP蒸气-植物表面交换的影响；量化相对湿度对POP蒸气-植物表面交换的重要性；确定UV辐射对POP在植物表面吸附的影响。实验将在受控的环境条件下进行，室内种植着常见的树状室内植物--无花果。由于试验室的大小及其再现环境条件的能力，这项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。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这个房间里进行研究。气候指标包括温度、相对湿度和紫外线辐射。将从环境空气中引入气相持久性有机污染物，以测量、模拟和预测低浓度下的动力学，并通过气流发生塔引入。***

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. ***