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

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 pesticides
2) to demonstrate the capability of the system at the field scale
3) to quantify fluxes of pesticides at the field and regional scale

Initially 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.

Aerosol science has a significant impact on a broad range of disciplines, extending from inhaled drug delivery, to combustion science and its health impacts, aerosol assisted routes to materials, climate change, and the delivery of agricultural and consumer products. Estimates of the global aerosol market size suggest it will reach $84 billion/year by 2024 with products in the personal care, household, automotive, food, paints and medical sectors. Air pollution leads to an estimated 30-40,000 premature deaths each year in the UK, and aerosols transmit human and animal infections. More than 12 million people in the UK live with lung disease such as asthma, and the NHS spends ~£5 billion/year on respiratory therapies. Many of the technological, societal and health challenges central to these areas rely on core skills and knowledge of aerosol science. Despite this, an Industrial Workshop and online survey (held in preparation for this bid) highlighted the current doctoral skills gap in aerosol science in the UK. Participating industries reported that only 15% of their employees working with aerosol science at doctoral-level having received any formal training. A CDT in aerosol science, CAS, will fill this skills gap, impacting on all areas of science where core training in aerosol science is crucial.

Impact on the UK aerosol community: Aerosol scientists work across governmental policy, industrial research and innovation, and in academia. Despite the considerable overlap in training needs for researchers working in these diverse sectors, current doctoral training in aerosol science is fragmentary and ad hoc (e.g. the annual Fundamentals of Aerosol Science course delivered by the Aerosol Society). In addition, training occurs within the context of individual disciplines, reinforcing artificial subject boundaries. CAS will bring coherence to training in the core physical and engineering science of aerosols, catalysing new synergies in research, and providing a focal point for training a multidisciplinary community of researchers. Working with the Aerosol Society, we will establish a legacy by providing training resources for future researchers through an online training portal.

Impact on industry and public-sector partners: 45 organisations have indicated they will act as CAS partners with interests in respiratory therapies, public health, materials manufacturing, consumer and agricultural products, instrumentation, emissions and environment. Establishing CAS will deliver researchers with the necessary skills to ensure the UK establishes and sustains a scientific and technical lead in their sectors. Further, it will provide an ideal mechanism for delivering Continuing Professional Development for the existing workforce practitioners. The activity of CAS is aligned to the Industrial Strategy Challenge Fund (e.g. through developing new healthcare technologies and new materials) and the EPSRC Prosperity Outcomes of a productive, healthy (e.g. novel treatments for respiratory disease) and resilient (e.g. adaptations to climate change, air quality) nation, with both the skilled researchers and their science naturally translating to long-lasting impact. Additionally, rigorous training in responsible innovation and ethical standards will lead to aerosol researchers able to contribute to developing: regulatory standards for medicines; policy on air quality and climate geoengineering; and regulations on manufactured nano-materials.

Public engagement: CAS will provide a focal point for engaging the public on topics in aerosol science that affect our daily lives (consumer products, materials) through to our health (inhalation therapeutics, disease transmission and impacts of pollution) and the future of our planet (geoengineering). Supported by a rigorous doctoral level training in aerosol science, this next generation of researchers will be ideally positioned to lead debates on all of these societal and technological challenges.