Predictions of air quality, human health impacts, climate change and the development of the best mitigation options for air pollution all require a sound understanding of the emissions of the pollutants into the air. As highlighted by the diesel emissions scandal, our understanding of emissions, frequently derived under laboratory conditions, often does not reflect the real world and as a consequence national and local governments are struggling to achieve the European air quality targets for nitrogen dioxide and fine particles (PM2.5). In addition to traffic sources, emissions from biomass burning and cooking are not represented in the current emission inventories and are subject to large uncertainties.
Direct measurements of emissions above urban areas provide a unique independent method to test the emission inventories and learn more about real-world pollutant emissions in the urban environment (Lee et al., 2015; Helfter et al., 2016). This studentship will temporarily relocate its office to the 35th floor of London’s BT Tower to measure emissions of a range of pollutants, including as part of planned large atmospheric measurement campaigns.
Key research questions
• How large are the real-world emissions of air pollutants across London’s city centre and how do they compare with emission inventories?
• How do these emissions change in space and time and what are the controlling factors?
• Which sources and compounds are important but not currently represented in the emission inventories?
• By analysing the fluxes of a large number of compounds in parallel, what can be learnt about the communalities and differences in sources?
• What do the flux measurements tell us about the chemistry the pollutants undergo within the first few minutes after emission into the atmosphere?
The studentship will use state-of-the-art instrumentation to measure pollutant fluxes from tall urban towers using the micrometeorological eddy-covariance flux measurement approach. This includes an Aerodyne High-Resolution Aerosol Mass Spectrometer (HR-ToF-AMS) and a recent version of the Ionicon Proton Transfer Reaction Mass Spectrometer (PTRMS). Compared with previous studies (Nemitz et al., 2009; Langford et al., 2010) both are now based on time-of-flight mass spectrometers, capable of detecting hundreds of compounds in the particulate and gas phase simultaneously (e.g. Karl et al., 2018). The student will contribute to the development of the analysis code to make maximum use of the mass spectral information from both instruments. Application of multi-factorial attribution techniques such as positive matrix factorisation (PMF) will enable the attribution of the emissions to various source types and fluxes will be analysed in relation to other pollutants such as CO, CO2 and NOx.
The measurements will primarily be made in the context of the intensive measurement periods of the OSCA (Integrated Research Observation System for Clean Air) project, (nerc.ukri.org/research/funded/programmes/clean-air/news/obs-periods), although additional opportunities may be pursued. Through this interaction the student will have the opportunity to interact with much of the UK Atmospheric Chemistry community.
A comprehensive training programme will be provided comprising both specialist scientific training and generic transferable and professional skills. In addition to access to a wide range of University courses, being based at CEH Edinburgh the student will also have access to CEH’s training programme. The student will further be instructed in micrometeorological flux measurement approaches, the operation of online chemical analysers based on time-of-flight mass spectrometer and statistical approaches for source apportionment such as PMF and ME-2. Training will be provided by CEH colleagues as well as through specialist summer schools for flux measurements and AMS/PTRMS data analysis.
You should have, or be expecting to achieve a good Honours or Master’s degree, or equivalent, in chemistry, physics, environmental science or a related discipline. You need to be technically minded and be able to learn to operate complex instrumentation and the numerical skills to analyse and process large volumes of data. Some knowledge of a computer scripting language (e.g. Fortran, Python) would be of advantage. Although based primarily in Edinburgh, you must be willing to work in London for two 6-week measurement campaigns.
Applications must be made directly to the E4 DTP https://www.ed.ac.uk/e4-dtp/how-to-apply
by the deadline of 9 January 2020
Equality & Diversity statement
The School of Chemistry holds a Silver Athena SWAN award in recognition of our commitment to advance gender equality in higher education. The University is a member of the Race Equality Charter and is a Stonewall Scotland Diversity Champion, actively promoting LGBT equality. The University has a range of initiatives to support a family friendly working environment. See our University Initiatives website for further information. University Initiatives website: https://www.ed.ac.uk/equality-diversity/help-advice/family-friendly
A 3.5 year PhD studentship (circa £15009 per annum) funded through the NERC Edinburgh Earth, Ecology and Environment (E4) Doctoral Training Partnership (www.ed.ac.uk/e4-dtp).
Eligibility and qualifications
Only UK/EU citizens resident in the UK for at least 3 years prior to the start of the studentship. Further details and stipend are at View Website.
Helfter, C., Tremper, A. H., Halios, C. H., Kotthaus, S., Bjorkegren, A., Grimmond, C. S. B., Barlow, J. F., and Nemitz, E.: Spatial and temporal variability of urban fluxes of methane, carbon monoxide and carbon dioxide above London, UK, Atmos. Chem. Phys., 16, 10543–10557, 2016.
Karl, T.; Striednig, M.; Graus, M; Hammerle, A.; Wohlfahrt, G.: Urban flux measurements reveal a large pool of oxygenated volatile organic compound emissions, PNAS, 115, 1186-1191, 2018.
Langford, B., Nemitz, E., House, E., Phillips, G. J., Famulari, D., Davison, B., Hopkins, J. R., Lewis, A. C., and Hewitt, C. N.: Fluxes and concentrations of volatile organic compounds above central London, UK, Atmos. Chem. Phys., 10, 627-645, 2010.
Lee, J.D.; Helfter, C.; Purvis, R.M.; Beevers, S.D.; Carslaw, D.C.; Lewis, A.C.; Møller, S.J.; Tremper, A.; Vaughan, A.; Nemitz, E.: Measurement of NOx fluxes from a tall tower in central London, UK and comparison with emissions inventories, Environ. Sci. & Technol. 49, 1025-1034, 2015.
Nemitz, E.; Jimenez, J.L; Huffman, J.A.; Ulbrich, I.M.; Canagaratna, M.R.; Worsnop, D.R.; Guenther, A.B.: An Eddy-Covariance System for the Measurement of Surface/Atmosphere Exchange Fluxes of Submicron Aerosol Chemical Species—First Application Above an Urban Area, Aerosol Sci. Technol., 42, 636-657, 2008.
How good is research at University of Edinburgh in Chemistry?
(joint submission with University of St Andrews)
FTE Category A staff submitted: 43.30
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