Improving our understanding of the role of biogenic emissions in urban air quality

This project aims to improve our understanding of the impact of natural emissions on particle pollution in cities. Exposure to poor air quality is the top environmental risk factor of premature mortality across the globe. Heart disease and strokes are the most common reasons for premature deaths due to air pollution, with other significant impacts including increased respiratory and cardiovascular disease and cancer. In many urban areas, one of the most important pollutants for health is particulate matter. Previous studies of the isotopic signature of carbonaceous material in particles indicate that a large fraction of particle mass is from natural sources. These sources include biomass burning, cooking and the oxidation of volatile organic compounds emitted from plants to form secondary organic aerosols (SOA).

A recent modeling study predicted biogenic emissions, in particular isoprene, dominate the production of SOA in Beijing in summer. However, atmospheric models can only incorporate a small number of sources and chemical reactions and need to be validated with field measurements. The relative importance of biogenic versus anthropogenic SOA is difficult to determine using conventional analytical techniques that look at the bulk functionality of particles. High-resolution chemical speciation can be used to investigate source specific tracers, however this approach typically only characterizes a very small fraction of the particle mass.

The University of York has developed an extensive mass spectral library of tracer molecules that can be used to chemically “fingerprint” specific volatile organic compound (VOC) emissions/sources. This has been built using a novel atmospheric simulation chamber, where a single VOC precursor can undergo atmospheric reactions in a controlled manner. Initially the student will improve the coverage of biogenic SOA tracers using a photochemical flow reactor developed at York to allow large quantities of SOA mass to be produced for a range of chemical analyses. The student will use this mass spectral library to compare and contrast the biogenic SOA signatures from time resolved filter samples taken from three large megacities (London, Beijing and Delhi).

The project will be supervised by Dr Jacqui Hamilton and Dr Andrew Rickard who are based in the world leading Wolfson Atmospheric Chemistry Laboratories The student will will use state of the art ultra-high resolution mass spectrometry to investigate the factors that control the oxidation and abundance of biogenic SOA and develop methods to estimate the total biogenic loading using source apportionment. It is expected that the student will collect particle samples during the Dehli-FLUX field campaign (in India) and from London field sites. The student will also carry out laboratory simulations of biogenic SOA formation using the photochemical flow reactor and use a range of analytical tools to identify the products of the reactions.

The successful PhD student will have access to a broad range of training workshops put on by the University of York as part of its Innovative Doctoral Training Program (iDTP). The studentship is offered as part of the SPHERES Doctoral Training Program which will provide additional training.

We appreciate that this PhD project encompasses several different science and technology areas, and we don’t expect applicants to have experience in many of these fields. The project is very well supported with experienced scientists and training in these new techniques and disciplines is all part of the PhD.

Although the PhD will be based at the University of York, to be considered you need to submit an application through the University of Leeds online application system selecting the programme ‘PhD Leeds/York NERC DTP’ and stating which project you are applying for. Please note that you can only apply for 1 project within the DTP.

Students with, or expecting to gain, at least an upper second class honours degree, or equivalent, are invited to apply.

Shortlisting will take place as soon as possible after the closing date and successful applicants will be notified promptly.
Shortlisted applicants will be invited for an interview to take place at the University of Leeds between 19 and 22 February 2018. Candidates will be interviewed by an academic panel.

The Department of Chemistry holds an Athena SWAN Gold Award and is committed to supporting equality and diversity for all staff and students. This PhD project is available to study full-time or part-time (50%).