Tropospheric oxidants are responsible for the degradation of trace gases emitted into the atmosphere, and thus determine fundamental Earth system processes including: the lifetime of climate gases such as methane; the production of secondary pollutants such as ozone and particles that impact on air quality; and the deposition of chemicals to ecosystems. Chlorine atoms (Cl) are the least understood of the atmospheric oxidants, with current estimates of their role ranging from highly important to negligible. This fundamental failing in our knowledge of atmospheric chemistry is due to a lack of measurements capable of informing the representation of Cl chemistry in air quality and climate models. In this project we will develop and deploy a new field measurement technique that will provide much needed information on atmospheric Cl chemistry, this in turn will be used to reduce uncertainties in global air quality and climate models.
In order to accurately represent atmospheric Cl chemistry we need to understand both how Cl atoms are produced and lost. The initial focus of this PhD project will be to develop a new field instrument to directly measure the total loss rate of atmospheric Cl atoms. Instruments to measure loss rates of the dominant atmospheric oxidant, OH, have previously been developed by Dr Edwards and others, and have been influential in identifying significant uncertainties in our understanding of atmospheric chemistry. A laboratory based technique capable of measuring oxidant loss rates has recently been developed in Dr Terry Dillon’s chemical kinetics group in the Wolfson Atmospheric Chemistry Laboratories (WACL), in collaboration with Prof Timo Gans in the York Plasma Institute. Working closely with Dr Dillon this lab method will be developed into a field ready instrument, and fully characterised both in the lab and in the real atmosphere.
In order to provide a direct test of our understanding of Cl atom reaction pathways in the real atmosphere, field measurements will then be made in both clean and urban-influenced environments to challenge our understanding of atmospheric Cl chemistry across a range of conditions. These field datasets will represent a major contribution to the study of atmospheric oxidation chemistry, and will enable chemical model simulations to be used to challenge and explore the true impact of Cl on processes important for both air quality and climate.
All research students follow our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills. All research students take the core training package which provides both a grounding in the skills required for their research, and transferable skills to enhance employability opportunities following graduation. Core training is progressive and takes place at appropriate points throughout a student’s higher degree programme, with the majority of training taking place in Year 1. In conjunction with the Core training, students, in consultation with their supervisor(s), select training related to the area of their research.
In addition to the departmental iDTC training, funding is available to support additional project related training such as the National Centre for Atmospheric Science Atmospheric Measurement Summer School (https://www.ncas.ac.uk/en/atmospheric-measurement-summer-school
) and the SOLAS Summer School (http://www.solas-int.org/solas-summer-school-18.html
). Funds are also available for a research visit to the group of Dr John Crowley at the Max-Planck-Institut für Chemie, Mainz, Germany, as part of an extended field deployment.
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. Chemistry at York was the first academic department in the UK to receive the Athena SWAN Gold award, first attained in 2007 and then renewed in October 2010 and in April 2015.