Opportunities

Determining the sources of daily personal inhalation exposure dose to indoor volatile organic compounds

Inhalation of volatile organic compounds (VOCs) can cause negative health effects such as triggering asthma attacks and long-term respiratory and cardiovascular diseases. Ambient indoor air contains a multitude of VOCs from sources such as cleaning and personal care products which all occupants are exposed to. However, those actively using the products are exposed to much higher, direct inhalation doses. 

This project will involve undertaking an extensive literature review of all potential sources of direct inhalation exposure, their VOC emissions (type and concentration), and typical usage scenarios to feed into a `storyline of exposure` which will examine the compound effects of inhaling VOCs from multiple sources both simultaneously and throughout the day. The student will have the opportunity to take lead of the direction of the project and will learn valuable skills in literature analysis and data handling which is essential for anyone looking to work within policy roles. The student will also be contributing to a larger body of ongoing work - creating an exposure model that will determine real-life inhalation of VOCs and the potential associated toxicity risks, which we hope could be used to inform and protect vulnerable people, such as those living with long-term respiratory conditions.

As there is no lab work required this project is suitable for students from any STEM background. 

 Supervisors Dr Amber Yeoman

Commercial cooking emissions to local air pollution in York

Everyday household activities produce air pollutants that can have negative health effects. Cooking, particularly, emits significant amounts of volatile organic compounds (VOCs), contributing to the formation of secondary organic aerosols and overall particulate matter. VOCs are released into the atmosphere from both commercial and domestic cooking activities, where they disperse or react with oxidants. However, in areas with a high concentration of restaurants, these emissions have the potential to make an important contribution to local air quality impacts. These impacts are however uncertain owing to a lack of information on the magnitude of the sources and how they disperse in the atmosphere.

It is challenging for traditional (fixed point) air quality monitoring stations to capture these VOC emissions due to their spatial variation of the sources and the rapid dispersion and atmospheric reactions. In contrast, mobile and fast-response measurements, such as the WACL Air Sampling Platform, provide a more effective way to study localised cooking emissions. 

This summer project aims to investigate the impact of commercial cooking emissions on air pollution. Building on the INGENIOUS Mobile Measurements project and findings from the 2023 summer project, this research will analyse restaurant emission hotspots in the City of York and identify key pollutants in those areas.

The summer student will receive training in big data analysis. Additionally, they will have the opportunity to learn air pollution measurement techniques and engage with scientists and academics in WACL, gaining valuable research and communication skills that will support their career development.   

Supervisor Sari Budisulistiorini  

Understanding iodine chemistry at the ocean surface with a computational model

Natural emissions from the Earth's surface play a large role in determining the chemistry of the atmosphere, influencing air quality, and climate change. Considerable attention is given to land-based emissions, however, the ocean is equally important in regulating the Earth's atmosphere. Iodine chemistry at the ocean surface is one way the ocean impacts air quality.  Iodine chemistry regulates tropospheric ozone which is detrimental to crop yields and human health, and is a greenhouse gas. Current representations of iodine chemistry at the ocean surface are limited in global atmospheric chemistry models. We have recently developed a new model of the chemistry and physics at the ocean surface, incorporating new experimental insights to improve our understanding of these important processes. However, many uncertainties remain. Experiments that can be conducted in this project include how the uncertainties in the rate coefficients and physical constants change iodine emissions, or the role of changing ocean salinity and pH on iodine emissions. In this project, you will learn how to run a chemistry box model, analyse and visualize experiment results in Python, and develop scientific software skills. 

Supervisor Dr Ryan Pound

Evaluation and analysis of ozone-depleting substance observations at Cape Verde Atmospheric Observatory since 2014.

The stratospheric ozone layer protects life on Earth by absorbing harmful radiation from the sun. In the early 1980s, scientists observed that this protective layer was thinning, which was soon attributed to the use of long-lived chlorofluorocarbons (CFCs). The potential of these CFCs to destroy stratospheric ozone led to the Montreal Protocol, a successful global treaty designed to phase out the production of these ozone-depleting chemicals. Due to this treaty, stratospheric ozone is predicted to recover this century, but areas of challenge remain to ensure that this recovery continues.

Emissions of very short-lived substances (VSLSs), such as dichloromethane and chloroform are growing and currently unregulated. Recent studies suggest these two VSLSs have the potential to offset ozone layer recovery by up to 30 and 8 years, respectively. Continuous ground-level measurements of VSLSs have been made at the Cape Verde Atmospheric Observatory for over a decade. This site allows for long-term measurements of a variety of atmospheric compounds to improve our understanding of changes in global air quality and atmospheric oxidation capacity. However, there has currently been very limited analysis of the VSLSs dataset. During this summer project, you will work to re-analyse the historical dichloromethane and chloroform measurements, utilising a newly developed processing procedure. Trends and seasonal profiles of these compounds will be explored. 

The summer student will be trained in basic programming skills (including R and RStudio) and will have the opportunity to present their findings to the wider research group toward the end of their project.

Supervisor Dr Beth Nelson and Lyndsay Ives

Upgrading Atmospheric Chemistry Instrument Calibration and Automation

Atmospheric measurements of trace gases are essential to evaluate air quality and climate, informing policy decisions and increasing our understanding of the negative effects of climate change. There is a wide range of instrumentation available to measure the components of the atmosphere whose concentrations span many orders of magnitude in concentration e.g. in the remote atmosphere you might measure nitrogen oxide (NO) concentrations between 1 part per trillion to 10 parts per billion. 

NO is routinely measured using chemiluminescence, and can measure NO2 via conversion - but newer technologies, such as laser induced fluorescence, boast substantially lower detection limits and faster time resolutions. Other methods that directly detect the presence of NO2 are also used. Instrument calibration and benchmarking is important to differentiate between these instruments, and understand the impact choosing one over another has on an experiment. 

The COZI lab is a bespoke laboratory for the intercomparison and calibration of atmospheric instruments and this year has received investment to upgrade its capabilities. This includes the installation of new sampling manifolds to support high flow rate instrumentation, and humidity control systems to assess water interferences on instrumentation. 

For this project, the student will help set up and work with the new instrumentation to develop calibration routines for NOx instrumentation with advanced humidity corrections. They will work with instrument operators to develop practical skills around how high quality atmospheric chemistry measurements are made. They will develop data analysis skills through the use of instrument automation software and the R programming language. 

Supervisors: Dr Will Drysdale (will.drysdale@york.ac.uk) and Dr Katie Read

Understanding the capabilities and limitations of canister sampling of volatile organic compounds

Volatile organic compounds (VOCs) are emitted into the atmosphere from a wide variety of sources and are significant precursors of tropospheric ozone and secondary organic aerosols.  Routine monitoring of VOCs in the atmosphere is made possible through direct mass spectrometric techniques, such as proton transfer mass spectrometric detectors (PTRMS), or more commonly using thermal desorption instruments coupled to a gas chromatograph.  The purchase and deployment of such instruments, however, brings considerable expense.  The use of whole air sampling (WAS) canisters is a commonly used and economical solution for VOC observations, allowing the collection of samples in the field (without the need for space/power) from multiple locations before returning them to the laboratory where a single instrument specialist can perform their analysis.

This project will evaluate the viability of using canisters to measure a range of VOCs in the atmosphere.  The successful candidate will develop and perform a series of tests comparing the performance of canister-based observations with on-line instruments as well as quantifying any associated uncertainties.  They will get full training and hands-on experience of gas chromatography coupled with flame ionisation and mass spectrometric detectors (commonly used in industrial analytical laboratories) as well as use of a variety of gas phase sample handing instrumentation.

This project is ideal for anyone considering a career in practical analytical/environmental chemistry and will provide the successful candidate with a broad understanding of different atmospheric measurement techniques.

Supervisors: Dr Jim Hopkins and Dr Tom Warburton