YES-27-Y-07: Sources and impacts of organic aerosol in the UK: Combining complex mixture analysis and machine learning to support informed decision making on UK Air Quality hazards

Sources and impacts of organic aerosol in the UK: Combining complex mixture analysis and machine learning to support informed decision making on UK Air Quality hazards

Primary Supervisor: Prof Jacqui Hamilton

Co-supervisor: Andrew Rickard

Co-supervisor: Daniel Bryant

The aim of this project is to develop a new framework that combines state of the art mass spectrometry with artificial intelligence approaches to both identify and predict the sources of organic aerosols. 

Annually exposure to fine particulate matter (PM2.5) in the UK is attributed to ~30-50,000 premature deaths and costs the UK economy around £27 billion through increases in acute and chronic health conditions. In 2024, the UK annual PM2.5 concentrations across urban background sites was 7.2 μg m-3, over the current WHO recommended threshold of 5 μg m-3. Reductions in anthropogenic secondary inorganic aerosol (SIA), through regulation has led to a significant reduction in PM2.5 concentrations and a subsequent increase in the organic aerosol (OA) fraction of PM2.5. However, episodes of high PM2.5 levels still occur, driven by local and regional processes, including emissions from wildfires and other climate change impacts, with both increases in ambient temperatures, reduced rainfall and a higher number of anti-cyclonic weather systems predicted to increase the frequency of harmful air pollution events in the UK. Improved PM composition measurements at the UK Air Quality Supersites have shown OA constitutes between 30-45 % of PM2.5 on an annual basis, but up to 85% during certain periods. However, this method only looks at bulk trends in composition and does not provide information on the sources of OA such as secondary OA (SOA), expected to be the dominant source. Policy interventions for reducing primary PM2.5  emissions and SIA formation are well established. In contrast, SOA represents a complex and poorly constrained source of PM2.5, and the relative contribution from natural and anthropogenic precursors is unknown. Improved source apportionment of UK OA is essential to develop evidence-based policies to effectively manage the impact of PM2.5 exposure on the population.

This project will combine laboratory experiments, field observations and data science approaches to address this important, yet poorly understood research gap. The student will collect ambient filter samples of PM2.5 at the Manchester AQ supersite. These filters will be analysed using liquid chromatography coupled to high resolution mass spectrometry. The project will focus on non-target analysis (NTA), where the full complexity of the organic aerosol will be characterised. This can result in very large datasets and a key challenge to date has been turning this into usable and actionable information.  Recent advances in AI provide a potential route to exploit these information rich datasets for source apportionment of OA and human health implications. The University of York is a world leader in NTA for OA composition and has extensive experience in identifying the primary emissions of OA and chemical pathways that lead to SOA. We will provide extensive training in both the analysis and data science components, and we do not expect students to have experience of these in advance.  The skills acquired in this area are highly sought after in academia, the public and private sectors. The student will have the opportunity to present directly to key stakeholders within government, and develop their ability to present findings to a variety of audiences. 

The student will work under the supervision of Professor Jacqui Hamilton, Dr Andrew Rickard and Dr Daniel Bryant and will be based at the Department of Chemistry’s Wolfson Atmospheric Chemistry Laboratory at the University of York. The Wolfson Atmospheric Chemistry Laboratories (WACL) are home to more than 75 researchers with interests in all aspects of atmospheric chemistry, from stratospheric ozone, through to urban pollution, personal exposure and health. The labs support an exceptional environment for research, have access to state-of-the-art facilities and include a range of different disciplines and researchers. 

Training and guidance will be provided in scientific writing, writing for broader audiences and presenting at national and international conferences. Students will be required to disseminate their research through presentations at annual symposium organised in collaboration with Defra and NCAS and international conferences. You will join a cohort of many other PhD students working in complementary areas, which will extend and enrich your experience during your PhD.

You will follow our core cohort-based training programme to support the development of scientific, transferable and employability skills, as well as training on specific techniques and equipment. https://www.york.ac.uk/chemistry/study/postgraduate-research/training-and-careers/