Opportunities

Low-cost Sensors

Dr Pete Edwards & Dr Stuart Lacy: Identifying real world case studies from air pollution low-cost sensors to facilitate policy decision making at a regional and national level

Air pollution is predicted by the World Health Organisation to become the world’s largest cause of preventable death by 2030, and improved monitoring is central to tackling human exposure. Low-cost air pollution sensors offer a paradigm shift in the way air pollution is measured but their use in the real-world remains limited, in part due to few examples of successful applications. Using a comprehensive field-based dataset generated by York researchers, this project will create a set of case studies to communicate best practice methodologies to end-users. With input from colleagues at York and Bradford local authority and Defra air quality teams, we will target key challenges in the practical use of these devices, and also feed into an upcoming Defra/BSI guidance document. Ultimately this work will help enable these exciting technologies for air quality management through the translation and communication of York led science.

Email: pete.edwards@york.ac.uk 

Biogenic Secondary Organic Aerosols

Dr Dan Bryant: Characterising biogenic secondary organic aerosol in summertime Manchester

Exposure to particulate matter less than 2.5 micrometres in diameter (PM2.5) is associated with a range of health effects. Secondary organic aerosol (SOA), a complex mixture of thousands of compounds, comprises a large fraction of PM2.5. SOA from biogenic sources (BSOA) is expected to become increasingly important due to reducing emissions of anthropogenic pollutants and changes in biogenic emissions from changing climate and weather conditions. As such, understanding the sources and contributions of BSOA to PM2.5 is important for the UK to reach current world health organisation guideline concentrations. The main aim of the project is to characterise BSOA tracers within PM2.5 samples collected in Manchester during summer 2022. The samples will be extracted and analysed using liquid chromatography coupled to high resolution mass spectrometry. The samples will then be screened using a newly developed mass spectral library which contains tracers from a range of biogenic precursors. The student will then be given scope to investigate the novel dataset. Overall, this project will provide lab experience in a research setting, analytical chemistry skills, experience using high resolution mass spectrometry and data analysis/visualisation experience using R.

Email: daniel.bryant@york.ac.uk 

Persistent Toxic Pollutants

Dr Matthew Jones & Prof Lucy Carpenter: Determining Organofluorine Breakdown Products in Complex Environmental Samples

Poly/perfluorinated alkyl substances (PFAS) are ubiquitous and persistent toxic pollutants. Trifluoroacetic acid (TFA) is a major contributor to the PFAS burden and considered an increasing environmental threat due to its projected growth from the breakdown of some hydrofluorocarbons. TFA is carried in rainfall to the earth, where it is found in acetate form, and it has been found to be widespread in drinking water.

This project will develop and optimise a procedure for the extraction and analysis of PFAS in aqueous samples. The optimisation will concentrate on determining low molecular weight PFAS including the anions difluoroacetate and trifluoroacetate. The optimisation procedure has three stages: (1) Extraction from environmental samples onto a weak anion exchange stationary phase and subsequent elution, (2) Ultra high-pressure liquid chromatography with a mixed mode column to separate PFAS for analysis, and (3) Orbitrap mass spectrometry to determine PFAS concentrations through targeted and non-targeted analysis. This project will concentrate on optimising all three phases of the procedure, minimising contamination, improving reproducibility and sensitivity and ensuring procedural blanks are robust and repeatable.

Ultimately, the developed method will be used to determine PFAS concentrations in rain and seawater and help improve understanding of their distributions, burden and environmental breakdown.

Email: matthew.jones@york.ac.uk 

Aerosol Pollution from Wildfires

Dr Andrew Rickard & Rhianna Evans: Identification of key biomass burning tracers in a Southeast Asian wildfire season

Wildfires are a significant source of air pollution through the formation of primary and secondary organic aerosol. Organic aerosol is a major constituent of PM2.5 (particulate matter less than 2.5 µm in diameter) which is regarded as one of the most dangerous forms of air pollution for human health. During the 2019 Southeast Asian wildfire season, PM2.5 filter samples were collected in Singapore for compositional analysis of organic aerosol using liquid chromatography coupled to mass spectrometry (LC-MS). The project will make use of a newly created biomass burning mass spectral library produced from controlled burn experiments. The library will be applied to identify key biomass burning signatures produced by the wildfires. This will allow important biomass burning species to be tracked during the wildfires and determine major contributing species to PM2.5.

Email: andrew.rickard@york.ac.uk 

Indoor Air Quality

Dr Amber Yeoman: Identifying Contaminant VOCs in Aerosolised Consumer Products and their Potential Sources

Recent studies have shown that aerosolised consumer products, such as deodorants and air fresheners, can contain dangerous volatile organic compound (VOC) contaminants which are released to air during product use. Most notably benzene, a toxic compound and known carcinogen, has been identified in high levels. This has sparked significant interest in both aerosolised product safety and the purity of aerosol propellant liquid petroleum gas (LPG) feedstocks. As these products are mainly used indoors, inhalation exposure is potentially extremely high due to poor ventilation and reduced dispersion.

This project will involve documenting and screening a large sample of aerosolised products available to purchase in the UK using an in-house built test chamber and gas-chromatography mass-spectrometry (GC-MS). Aerosol industry stakeholders are keen to understand the seriousness of the problem and how it effects their products, so there is scope for collaboration with them to identify the sources of these dangerous species by identifying patterns in the contaminants present between different products, brands, and propellant gas sources.

Email: amber.yeoman@york.ac.uk

Vehicle Emissions

Dr Naomi Farren: Using new remote sensing measurement techniques and data processing methods to investigate vehicle emission behaviour

Increasingly stringent emission regulations have led to considerable reductions in the amount of NOx (NO + NO2) emitted from vehicles, yet the adoption of more complex emission control technologies has heightened concern over the fraction of NOx emitted as NO2, the more harmful component. New techniques for measuring vehicle exhaust emissions have been developed as part of the CARES project (https://cares-project.eu/), in addition to a new data processing method for quantifying vehicle exhaust emission ratios (https://doi.org/10.1016/j.scitotenv.2023.162621). The aim of this project is to use the data processing method to analyse multiple datasets collected using the new measurement techniques. Data collected at a vehicle test track will be used to assess factors affecting the fraction of NO2 in NOx, such as driving conditions and aftertreatment system tampering. Vehicle emission measurements collected on a busy street in Milan, Italy, will be used to investigate NO2/NOx ratios under real world driving conditions, and mobile measurements conducted across the city will be used to evaluate the spatial variation in NO2/NOx. There will also be an opportunity to assist with setting up a new trace gas atmospheric instrument to be used for field measurements.

Email: naomi.farren@york.ac.uk 

Urban Air Quality

Dr Will Drysdale & Dr Beth Nelson: Investigating Urban Air Quality in Nairobi and York

Ground level ozone (O3) is a secondary air pollutant, produced from the photochemistry of volatile organic compounds and nitrogen oxides. It is a pollutant of concern due to its deleterious effects on human health and agriculture. Pollution in urban environments can be a source of high O3 concentrations which when coupled with their high population densities can lead to large health burdens.

While there are many O3 monitoring stations worldwide, they are primarily focused in high income countries, and some upper-middle income countries (check out the interactive map here: explore.openaq.org for an idea!). Our research group has recently donated an O3 monitor to Nairobi to be used in their air quality monitoring programme. This project aims to explore the data collected from this deployment, and search for other sources to contextualise it.

Closer to home, we have also recently deployed O3 and NO2 instruments at a site at York St. John university, where they are installing a green wall with an aim to improve campus air quality. Using data from these monitors and those from the established air quality monitoring network in York, this project will take a preliminary look at whether the impacts of the green wall are measurable.

This project will provide opportunities for the student to learn about how air quality monitoring data is collected and provided, and advance their data handling skills. They will also work in the calibration laboratories to understand the quality assurance procedures monitoring equipment is subject to and, time allowing, visit a monitoring station operated by WACL at the Aviva building in York.

Email: will.drysdale@york.ac.uk or beth.nelson@york.ac.uk