Project highlights

  • Probing for self-organisation in real atmospheric aerosols for the first time
  • Sampling & analysing of urban cooking emissions in Birmingham synergistically linked to tailored laboratory experiments
  • Employing state-of-the-art laboratory methods to establish the atmospheric importance of aerosol self-organisation

Overview

The project will investigate the potential impact on cloud formation & urban pollution of self-organisation within aerosol particles. Atmospheric aerosols arise from human activity, and influence whether clouds form, how quickly molecules degrade and therefore how long they persist in the atmosphere. Fatty acids & esters are key components of urban aerosols and emitted in substantial quantities from cooking.

So far little consideration has been given as to how these molecules arrange themselves within atmospheric aerosols, and the effects this organisation may have on aerosol properties. Fatty acids are “surface-active” molecules (“surfactants”), possessing water-loving heads & water-hating tails, causing such molecules to accumulate at the outside of water droplets thus determining key aerosol surface properties, such as the ability to nucleate clouds, even at low concentrations. From laboratory experiments, it is known that, within water droplets, surfactants self-organise to form a rich variety of 3–D structures including crystal-like arrays called “lyotropic phases” containing nanoscale sheets, spheres (“micelles”) or cylinders, strongly affecting physical properties including diffusion, viscosity & water uptake. These physical properties are key in an atmospheric context, e.g. for cloud formation & chemical lifetimes of organic molecules, with implications for local weather & human health.

We will collect urban aerosols in Birmingham –with particular focus on cooking emissions– and then study the 3–D structure of atmospheric samples & aerosol proxies using complementary cutting-edge methods with an exciting potential to make a step-change in the understanding of the effects of the aerosol’s internal structure on chemical reactions, cloud nucleation, and the transport speed through the droplets & on atmospheric lifetimes, and thus for their impact on local weather, urban air quality and human health.

Host

University of Birmingham

Theme

  • Climate and Environmental Sustainability

Supervisors

Project investigator

  •  Dr Christian Pfrang (University of Birmingham)

 

Co-investigators

  • Dr Ben Langford (CEH Edinburgh)
  • Prof. Zongbo Shi (University of Birmingham).

How to apply

Methodology

We will collect and analyse urban aerosol samples in Birmingham benefitting from existing infrastructure, expertise and state-of-the-art instrumentation available within GEES at Birmingham.  We will then investigate lyotropic phases formed in these atmospheric samples; this work will be complemented by studying well-defined “proxy” mixtures with atmospherically realistic surfactant composition, temperature and humidity, in “bulk” samples of surfactant & water, films and levitated droplets. We will probe the self-organisation using a technique for investigation of nanoscale structure (Small-Angle X-ray Scattering, SAXS), and the viscosity, diffusion & water uptake using complementary methods.

Applying these laboratory techniques for the first time to real atmospheric aerosols collected in Birmingham is an essential step to establish the real-world impact of lyotropic phases. The ultimate aim is to establish the importance of the nanoscale self-organisation within aerosols for atmospheric processes – potentially resolving key unknowns in the behaviour of aerosols, clouds & urban air pollutants.

Training and skills

Training on literature search and scientific writing will be provided during weekly supervisory meetings. S/he will benefit from expertise within GEES with 15+ academics leading closely related research with opportunities to present research, discuss challenges, collaborate and get an understanding of the broader context.

Partners and collaboration

This project is co-developed with the Centre for Ecology and Hydrology (CEH). Co-I Dr Langford has extensive experience in field sampling, specifically using state-of-the-art instruments such as PTR-Qi-TOF-MS systems available both at CEH and within GEES. Co-I Prof. Shi is science coordinator of the Atmospheric Pollution and Human Health in a Chinese megacity (APHH-China) programme and coordinated two successful field campaigns in Beijing. Dr Langford and Prof. Shi thus provide outstanding expertise in field studies synergistically complementing Dr Pfrang’s expertise in laboratory studies of self-organised samples. MPIC is Dr Pfrang’s project partner on a new NERC grant workpackage on modelling oxidation of self-assembled atmospheric materials.

Further details

For further information, please contact Dr Christian Pfrang, School of Geography, Earth & Environmental Sciences, University of Birmingham (c.pfrang@bham.ac.uk; 0121 414 5519; webpage: https://www.birmingham.ac.uk/staff/profiles/gees/pfrang-christian.aspx).


Applications need to be submitted via the University of Birmingham postgraduate portal, https://sits.bham.ac.uk/lpages/LES068.htm, by midnight 11.01.2021. Please first check whether the primary supervisor is within Geography, Earth and Environmental Sciences, or in Biosciences, and click on the corresponding PhD program on the application page.

This application should include

  • a brief cover letter, CV, and the contact details for at least two referees
  • a CENTA application form
  • the supervisor and title of the project you are applying for under the Research Information section of the application form.

Referee’s will be invited to submit their references once you submit your application, but we strongly encourage applicants to ensure referees are aware of your submission and expecting a reference request from us. Students are also encouraged to visit and explore the additional information available on the CENTA website.

Possible timeline

Year 1

Literature review, training in generic research techniques (e.g. research ethics, project planning & laboratory safety), and subject-specific training in collecting & analysing aerosol samples, learning & applying laboratory-based analytical methods (aerosol and gas handling, ultrasonic levitation, SAXS, Raman microscopy and complementary techniques).

Year 2

Continue urban sample collection; optimise extraction methods and characterise composition of urban samples; laboratory experiments on atmospheric aerosol proxies with ultrasonic levitation, in bulk mixtures and thin films; write-up of initial data for an international conference towards the end of year 2 (poster or oral presentation); contribute to beamtime applications at -Diamond Light Source and MAXIV, Sweden.

Year 3

Complete urban sample collection; introduce urban samples into laboratory experimental systems and carry out optimised laboratory experiments; participate in beamtime experiments and contribute urban cooking samples; start writing up research papers and PhD thesis; participate at a second international conference towards the end of year 3 (oral presentation if possible).

Completion of thesis and writing of papers.

Further reading

BBC News (2017) ‘Deep fat fryers may help form cooling clouds’ Available at: https://www.bbc.co.uk/news/science-environment-42081892 (Accessed: 28 October 2019).

Chemistry World (2014) ‘Out of the frying pan and into the atmosphere’ Available at: https://www.chemistryworld.com/news/out-of-the-frying-pan-and-into-the-atmosphere/7402.article (Accessed: 28 October 2019).

CNN (2017) ‘How your scalding hot deep fryer might help cool the weather’ Available at: https://edition.cnn.com/2017/11/23/health/deep-fryers-and-cooling-clouds-trnd/index.html (Accessed: 28 October 2019).

Diamond Light Source Science Highlight (2017) ‘Cooking oil and clouds’ Available at: https://www.diamond.ac.uk/Science/Research/Highlights/2017/atmosperic-aerosols-B21.html (Accessed: 28 October 2019).

MAXIV Science Highlight (2017) ‘Are cooking fats affecting clouds?’ Available at: https://www.maxiv.lu.se/news/cosaxs-cooking-fat/ (Accessed: 28 October 2019).

Milsom, A., Squires, A. M., Woden, B., Terrill, N. J., Ward, A. D.  and Pfrang, C. (2020) “The persistence of a proxy for cooking emissions in megacities: a kinetic study of the ozonolysis of self-assembled films by simultaneous Small & Wide Angle X-ray Scattering (SAXS/WAXS) and Raman microscopy” Faraday Discussions, https://doi.org/10.1039/D0FD00088D

Pfrang, C., Rastogi, K., Cabrera E., Seddon, A. M., Dicko, C., Labrador, A., Plivelic, T., N. Cowieson and Squires, A. M. (2017) ‘Complex Three-Dimensional Self-Assembly in Proxies for Atmospheric Aerosols.’ Nature Communications, 8, 1724. doi: 10.1038/s41467-017-01918-1.

Seddon, A. M., Richardson, S., Rastogi, K., Plivelic, T., Squires, A. M. and Pfrang, C. (2016) ‘Control of Nanomaterial Self-Assembly in Ultrasonically Levitated Droplets’ Journal of Physical Chemistry Letters, 7, 1341–1345. doi: 10.1021/acs.jpclett.6b00449.

COVID-19

This experimental project includes use of large-scale facilities and will potentially be affected by laboratory and facility closures. All facilities are available in the UK, so no international travel is essential (alternative facilities exist in Europe in case access to UK facilities becomes limiting).  Experimental data will be obtained in short beam-time experiments and facilities run Covid-19 resilience programmes (e.g. if no user access is possible, experiments are carried out by mailing in samples). Many experiments can be conducted by a single person even if collaborative experimentation would not be feasible; a substantial proportion of the project will be highly flexible analysis and modelling of experimental data; some experimental data were collected already and back-up field samples are ready for use; interaction with CEH/MPIC can be carried out electronically.