Project highlights

  • Research into the cutting-edge field of urban aerosol and air quality with potential implications for Covid-19 vulnerability.
  • Work with world-leading scientists and space agencies on novel, challenging satellite remote sensing methods for aerosol determination.
  • Provide the first high resolution, spatially continuous insights into urban aerosols in UK cities and selected international megacities.


Airborne particles play a critical role in environmental science with major implications for climate and air quality. Particulate matter (aerosols) is one of the most important factors for poor air quality and most of the estimated 4 million excess deaths per year stem from cardiovascular and respiratory diseases caused by particulate matter in the air. Correlations of high densities of aerosols (smog) with transmission and morbidity data from Covid-19 have suggested statistical links, at least, between pollution, Covid vulnerability (e.g. respiratory), urban density and disease transmission. However, aerosols are highly complex and variable, especially in cities, due to their diverse sources (vehicle exhaust, industry, fuel-burning etc.) and atmospheric reactions. Existing ground-based networks can provide an excellent temporal but only a very incomplete spatial view of urban aerosol distributions. For many cities, a new form of observation is required to provide aerosol air quality information to all and would transform our ability to assess aerosol distributions and their likely health impacts.

Optical instruments on satellites are an important resource to monitor aerosols from space. The recently launched Sentinel-2 can fundamentally change our approach to urban aerosols by allowing us to derive aerosol information on an unprecedented scale of tens of meters (potentially 10 m). This is the relevant scale to pinpoint different aerosol sources (roads, industrial facilities etc.), to diagnose aerosol variations across urban conurbations and the impact of transport pathways within a city.

In this project, the challenges of the science require new methods to derive the aerosol concentrations so the student will create a novel aerosol dataset with very high spatial resolution and use it to challenge our current understanding of urban aerosols. The exciting science that follows will be of great interest to other scientists, to the public and to policy makers. Results will be published in high quality journals and shared with government and local authorities, particularly through contacts in the Department for Environment, Food and Rural Affairs. CENTA partners have some great strengths in this type of research so the project will build links across CENTA.


University of Leicester


  • Climate and Environmental Sustainability


Project investigator

  • Prof. John Remedios (U. Leicester)



  • Prof. Hartmut Boesch
  • Dr. Josh Vande Hey (Leicester)
  • Dr. Elisa Carboni (NCEO, RAL).

How to apply


The student will develop and apply innovative, aerosol-specific methods to the Sentinel-2 satellite to deduce aerosol information for at least 2019 and 2020. Methods are cutting-edge because they exploit state-of-the-art mathematical methods ranging from optimisation techniques to artificial intelligence machine learning. Key to analysis of Sentinel-2 data will be careful testing of new fast methods to simulate satellite signals and the investigation of methods to separate aerosol signatures from the surface reflectance.

The new aerosol data will be used to assess air quality over the critical time periods pre-Covid and post-Covid.   The project will focus initially on UK cities (e.g. Leicester, Birmingham) with careful evaluation of the new dataset against ground-based networks and remote sensing, upward-looking laser sensors.  The student will use the data to investigate observed changes in the aerosol distributions. Finally, they will apply the retrieval method to selected megacities across the world.

Training and skills

The student will be part of the Leicester Earth Observation Science group which provides an exciting cross-disciplinary environment. The student will obtain a wide range of skills and expertise in satellite remote sensing, carbon cycle and wider environmental science. Specific training will be provided by the supervisory team and CENTA with many further opportunities, e.g. summer schools, workshops and University training (e.g. computing). The student will also benefit from the National Centre for Earth Observation (NCEO) which provides numerous training opportunities from data visualization to presentation skills alongside rewarding opportunities to interact with researchers and PhD students.

Partners and collaboration

The project is primarily a partnership between researchers at the University of Leicester and NCEO providing links to knowledge of urban pollution, health impacts and satellite methods of importance to this project. The student will have opportunities to build research collaborations with other teams in CENTA, particularly at Birmingham which will be a test area for the student’s investigations and where there is also high quality urban research.

Further details

For further information, please contact the primary supervisors: the supervisors Prof. John Remedios ( and Prof. Hartmut Boesch (

For more details about the EOS group at Leicester, please see

For more details about NCEO, please see

Possible timeline

Year 1

Training in satellite remote sensing methods and aerosol retrieval methods. Evaluate different aerosol datasets for cities (UK aerosol models, EO networks such as Aeronet, ground-based public and research networks) and setup initial retrieval method. Attend summer school.

Year 2

Apply retrieval method to Sentinel2 and generate dataset for UK cities. Evaluate the aerosol data from Sentinel2 and comparison to ground-based aerosol data and air quality model data. Presentation at NCEO national EO conference and an international conference.

Year 3

Extend the Sentinel2 aerosol retrieval to cities in Asia, particularly India and China. Presentation at international conference.

Further reading

Kramer, L. J., R. J. Leigh, J. J. Remedios, and P. S. Monks (2008), Comparison of OMI and ground-based in situ and MAX-DOAS measurements of tropospheric nitrogen dioxide in an urban area, J. Geophys. Res., 113, D16S39,doi:10.1029/2007JD009168.

Li, Z.; Roy, D.P.; Zhang, H.K.; Vermote, E.F.; Huang, H. Evaluation of Landsat-8 and Sentinel-2A Aerosol Optical Depth Retrievals across Chinese Cities and Implications for Medium Spatial Resolution Urban Aerosol Monitoring. Remote Sens. 2019, 11, 122.

Boesch, H.; Potts D.; Remedios, J.; D. 2020.  Using Sentinel-5P to monitor Air Quality changes since the Coronavirus outbreak: a UK Expert View.

NASA Earth Observatory, Haze over the UK,

ESA Sentinel-2 web page,


The current project is reasonably Covid-19 proof; it does not involve laboratory or field work. The risks are being mitigated:

  • Lack of access to computer infrastructures and datasets: a) access to multiple computing systems; b) multiple nodes for data download; c) close liaison with Leicester/NERC Services.
  • Lack of access to supervisory team: a) use multiple online meeting packages including instant access Teams calls; b) use of safe, physical meetings where allowed by University policies; c) care to student welfare.
  • Need for online access to training: Leicester is using blended IGNITE approach. Supervisory team have run online conferences and teaching.