Source-specific quantification of ammonia emissions

Background

Ammonia (NH3) has an ever-growing influence on air pollution in the UK and worldwide with numerous considerable impacts such as the formation of secondary particles and nitrogen deposition. Despite this importance, the magnitude, temporal and spatial variability of NH3 emissions remain highly uncertain. The need to reduce NH3 emissions in Europe as part of controlling the long-range transport of air pollution is well-established through national and international commitments. The lack of robust evidence in this area is a major limitation in understanding of current and future impacts of NH3 emissions in the UK and beyond; and is out of step with the multiple adverse impacts of NH3 in the wider environment. This project aims to significantly improve the quantification of NH3 emissions through targeted measurements using a mobile laboratory.

Objectives

The project will use a dedicated new, highly capable instrument for measuring NH3 in the atmosphere based on Quantum Cascade Laser Absorption Spectroscopy. The open-path technique eliminates many of the measurement challenges associated with NH3, as well as providing new ways in which to make measurements. The student will add the instrument to the our mobile laboratory to enable fast (up to 10 Hz) measurements of NH3 with existing capability to measure NOx, CO, SO2, VOCs, particulate matter (1 to 10 μm), CH4, and CO2.

The mobile laboratory will offer new approaches for the targeted quantification of a wide range of NH3 sources using a range of measurement approaches:

● Point sampling – where the instrument is used at a fixed location and individual plumes are measured e.g. individual road vehicles;

● Plume transect measurements – where the mobile lab is used to sample across dispersing plumes downwind of different source types. This approach is especially well-suited to quantifying area sources such as from agriculture. The student would use the ADMS dispersion model to conduct inverse modelling to back calculate source strengths.

● Mobile mapping is a technique refined at York for combustion pollutants where the spatial distribution of concentrations is quantified but to date has not been possible for NH3.

The early part of the PhD would focus on developing a plan for prioritising sources for measurement based on their importance and current knowledge concerning emissions.

Training

Extensive training will be provided, which is supported by a budget of £7,500. This will encompass specific training on the use and calibration of the instruments and use of the York mobile laboratory, where no previous instrument knowledge is required. Targeted fieldwork will provide rich new data sets addressing significant gaps in scientific knowledge.

Students will be required to take part in an annual symposium organised in collaboration with Defra and NCAS. Students will have an opportunity to spend time work-shadowing or undertaking a placement in the Defra air quality teams towards the end of their PhDs; an additional up to £2000 funding for this is also provided by the studentship programme.

Comprehensive training will be provided on data analysis using the R programming language. Our group has a track record of developing innovative, new approaches to working with data leading to many high profile publications. The skills acquired in this area are highly sought after in academia, the public and private sectors. Past students have successfully attained exciting positions for a range of employers based on the skills developed during their PhDs in our group.

Training and guidance will be provided in scientific writing, writing for broader audiences and presenting at national 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. Training includes employability and professionalism, graduate teaching assistant training and guidance on writing papers. https://www.york.ac.uk/chemistry/postgraduate/training/idtc/idtctraining/  

Equality and Diversity

The Department of Chemistry holds an Athena SWAN Gold Award and is committed to supporting equality and diversity for all staff and students. The Department strives to provide a working environment which allows all staff and students to contribute fully, to flourish, and to excel: https://www.york.ac.uk/chemistry/ed/

As part of our commitment to Equality and Diversity, and Widening Participation, we are working with the YCEDE project (https://ycede.ac.uk/) to improve the number of under-represented groups participating in doctoral study.  

Entry requirements 

You should hold or expect to achieve the equivalent of at least a UK upper second class degree in Chemistry or a relevant related subject. 

For more information about the project, click on the supervisor’s name above to email them. 

For more information about the application process or funding, please click on email institution.

Guidance for applicants: https://www.york.ac.uk/chemistry/postgraduate/apply/

Submit an online PhD in Chemistry application: https://www.york.ac.uk/study/postgraduate/courses/apply?course=DRPCHESCHE3

Applications may close early if a suitable applicant is found.

The start date of the PhD can be 16 September 2024 or 1 January 2025.