Introduction
Halocarbons – a group of chemicals used widely as refrigerants, foam blowing agents, solvents, and propellants – have had a major influence on the stratospheric ozone layer and climate since the mid-20th century. Since the signing of the Montreal Protocol in 1987, growth rates of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) have declined substantially due to regulation. There remain however substantial scientific challenges that must be addressed to ensure the continued success of the Montreal Protocol. In 2018, emissions of the major ozone depleting substance, CFC-11, were found to have increased despite its global production ban (Montzka et al., 2018). Around half of the new global emissions originated from eastern China and subsequent enforcement action taken in China has avoided a potentially substantial delay in ozone layer recovery and additional climate warming. However, the origin of the remaining half of the new emissions is still unknown due to the sparse observation network. Furthermore, it is not known whether illegal production has occurred for many other ozone depleting substances, some of which are emerging in the atmosphere. An additional challenge is presented by the rapid growth in unregulated anthropogenic emissions of very short-lived substances (VSLS) such as dichloromethane (CH2Cl2) and chloroform (CHCl3). The very uncertain contribution of natural oceanic sources to these VSLS hampers efforts to establish their anthropogenic emission distributions and trends. Even relatively small oceanic emissions of these compounds have the potential to contribute to the lower stratospheric ozone if emissions occur in the tropics.
Project Summary
This project will expand our atmospheric halocarbon automated measurements at the Cape Verde Observatory (CVO) and potentially at the Hateruma (HAT) station in Japan to include a wider range of established and emerging ozone depleting substances. You will also collect new air and seawater VSLS chlorine measurements at Cape Verde to investigate and parametrise in situ ocean production. Thus, you will determine patterns and trends in emerging anthropogenic ozone depleting substances and better constrain natural emissions of short-lived ozone depleting compounds not controlled under the Montreal Protocol.
The current GC-MS system at the CVO, operating since 2014, has very recently been upgraded to trap gases at a much lower temperature than the previous system, enabling the measurement of more volatile halocarbons (CFCs, HCFCs, HFCs). In this project, you will:
-test and harmonise GC column combinations with those used by other groups to allow comparison of relative retention times for new halocarbon species,
-establish calibration scales for compounds not previously measured at the CVO via an intercomparison programme,
-routinely analyse the continuous atmospheric halocarbon data from the CVO and HAT stations,
-establish a program of monthly seawater sampling upwind of the CVO for measurements of CH2Cl2, CHCl3 and other, predominantly natural, VSLS by purge and trap GC-MS, and calculate their oceanic “saturation anomalies”,
-analyses these saturation anomalies for patterns and trends to allow scale-up of these emissions to the tropical ocean.
Why this project?
The project is well aligned with the Department’s vision to conduct interdisciplinary research targeting societally important advances. The project is within one of the Department’s key areas of strength, of atmospheric chemistry and biogeochemical cycling. It will bring innovation to advance the science of halocarbon measurement and emission quantification and will bring new insight into this complex field. Results from this work will be fed into the WMO/UNEP Stratospheric Ozone Assessment (2026), which provides the research community with an up-to-date scientific assessment of ozone depleting substances and their impact on stratospheric ozone.
All Chemistry research students have access to our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills: https://www.york.ac.uk/chemistry/postgraduate/training/idtc/
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/.
For more information about the project, click on the supervisor's name above to email the supervisor. For more information about the application process or funding, please click on email institution
This PhD will formally start on 1 October 2023. Induction activities may start a few days earlier.
To apply for this project, submit an online PhD in Chemistry application: https://panorama-dtp.ac.uk/how-to-apply/
You should hold or expect to achieve the equivalent of at least a UK upper second class degree in Chemistry or a related subject. Please check the entry requirements for your country: https://www.york.ac.uk/study/international/your-country/
Eligibility and How to Apply
See our How to Apply page.
The NERC Panorama DTP are hosting ‘Demystifying the PhD application process’ webinars on the 9th and 12th December – sign up now!
The minimum English language entry requirement for postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.
Equal Opportunities:
Within the NERC Panorama DTP, we are dedicated to diversifying our community. As part of our ongoing work to improve Equality, Diversity and Inclusion within our PhD funding programme, we particularly encourage applications from the following identified underrepresented groups: UK Black, Asian and minority ethnic communities, those from a disadvantaged socio-economic background, and disabled people. To support candidates from these groups, we are ringfencing interviews, providing 1-2-1 support from our EDI Officer (contact Dr. Katya Moncrieff) and hosting a bespoke webinar to demystify the application process. Candidates will always be selected based on merit and ability within an inclusive and fair recruitment process.
Continue with Facebook
