Towards a better understanding of the lifecycle of Pesticides in the Atmosphere

由于农药是在区域范围内和背景环境中进行测量的，因此有一条从施用地区向这些偏远地区迁移的路径。考虑到距离尺度，这很可能涉及通过大气的迁移，要么是气相迁移，要么是颗粒相迁移，或者很可能是两者兼而有之。有潜在的健康影响，在近场规模的农场工人或附近的居民和以前的工作已经调查了近场运输期间的应用程序。目前还没有数据说明农药在施用后的排放如何演变，以及如果有任何环境因素控制进一步的排放，则是哪些环境因素。在更广泛的范围内也缺乏数据。该博士项目将研究农药从施用点到区域规模的通量。现在可以使用在线方法对气相中的农药进行质谱检测。UoM在颗粒物和气体的涡流相关通量测量方面拥有广泛的专业知识。基本上，该技术利用感兴趣的组分浓度的快速变化与垂直风速之间的相关性来导出通量。化学电离质谱法（CIMS）已被证明能够测量气相中的农药，这在芬兰以前已被应用于有机物的涡流相关测量。UoM CIMS可以发展成这样的流量系统，用于检测气相排放流量。UoM仪器还可以配备电喷雾电离入口（EESI），允许在线测量农药的颗粒相浓度，也可以在通量模式下操作。目标是：1）开发一个用于农药气相和颗粒相表征的通量系统2）在田间尺度上展示该系统的能力3）在田间和区域尺度上量化农药通量最初的工作将涉及开发CIMS-ToF-MS仪器和用于分析数据的分析工具的工作知识。EESI进气道也将安装，学生将努力理解这个系统。我们在美国有合作者，他们已经在CIMS仪器的涡流相关版本上工作，并将协助CIMS和EESI配置的开发，两者都将使用相同的质谱仪系统。该系统的开发将是第一年和第二年研究的第一部分的主要任务。然后，将在一系列实地研究中对该系统进行测试，旨在评估在一系列环境条件下以及围绕诸如耕作和收获等具体耕作做法施用期间和施用之后的排放通量。还将在对照试验期间进行粒子通量测量。然后，可以通过在广泛施用农药之前、期间和之后的一段时期内审查区域范围内农药的浓度来扩大这项工作，以审查区域负担。实现这一目标的一种方法是，以具有一般季节性周期的飞机飞行为目标，并将其与适当边界层条件下记录的排放活动联系起来。博士学位将涉及仪器开发以及数据分析和解释。

Since pesticides have been measured on regional scales and in the background environment there is a pathway for transport to these remote locations from the area of application. Given the distance scales this is likely to involve transport via the atmosphere, either in the gas phase or particle phase, or in all likelihood both. There are potential health impacts at the near field scale to farm workers or nearby inhabitants and previous work has investigated this near field transport during periods of application. There is an absence of data on how the emission of pesticides evolves after application and what environmental factors, if any control further release. There is also a lack of data at the wider scale. This PhD project will examine the fluxes of pesticide from the point of application to the regional scale.Mass spectrometric detection of pesticides in the gas phase is now possible using online methods. UoM has extensive expertise in eddy correlation flux measurements of particulates and gases. Essentially the technique uses correlation between rapid changes in the component concentration of interest and the vertical wind velocity to derive a flux. Chemical ionisation mass spectrometry (CIMS) has been shown to be capable of measuring pesticides in the gas phase and this has previously been applied to eddy correlation measurements of organic matter in Finland. The UoM CIMS can be developed into such a flux system and used to examine gas phase emission fluxes. The UoM instrument can also be fitted with an electrospray ionisation inlet (EESI) which allows online measurement of the particle phase concentration of pesticides and this can also be operated in flux mode. The objectives are:1) to develop a flux system for both the gas and particle phase characterisation of pesticides2) to demonstrate the capability of the system at the field scale 3) to quantify fluxes of pesticides at the field and regional scaleInitially the work will involve developing a working knowledge of the CIMS-ToF-MS instrument and the analysis tools used to analyse the data. The EESI inlet will also be fitted and the student will work on understanding this system. We have collaborators in the USA who have already worked on an eddy correlation version of the CIMS instrument and will assist with the development of the CIMS and the EESI configurations, both of which will use the same mass spectrometer system. The development of this system will be a major task of the first year and the first part of the second year of the study. The system will then be tested in a series of field studies designed to assess the emission fluxes during and following application under a range of environmental conditions and around specific farming practices such as ploughing and harvesting. Particle flux measurements will also be made during controlled trials. This work can then be extended by examining the concentrations of pesticides at the region scale during a period before, during and after extensive pesticide application to examine the regional burden. A way of achieving this could be to target aircraft flights with generic seasonal periods and link these to documented activity in emission under suitable boundary layer conditions. The PhD would entail instrument development, as well as data analysis and interpretation.