Volcanic emissions of environmentally-reactive trace elements

The cover image shows field sampling of volcanic emissions using a drone at Fagradalsfjall eruption, Iceland in 2021


Approximately one billion people live within 100 km, a distance within which they may be exposed to intermittent or chronic pollution caused by volcanic gases and aerosol particulate matter (PM). Depending on the meteorological conditions, populated areas can be exposed to highly variable and potentially dangerous concentrations of volcanic pollutants. Key air pollutant species in volcanic emissions include sulphur dioxide gas (SO2),  PM2.5 and PM1 (particulates smaller than 2.5 and 1 microns, respectively). Volcanoes can also be a large and long-lived source (Figure 1) of environmentally-reactive trace elements (ERT), which can impact the environment and health especially through chronic exposures.

Figure 1: The daily emission rate of several environmentally-reactive trace elements from individual, long-lived volcanic eruptions (coloured bars) can be comparable to total anthropogenic emissions from large countries (greyscale bars). Figure from Ilyinskaya et al., 2021.

There are several important knowledge gaps, which you will address in this project: What are the dispersion patterns and atmospheric lifetimes of the different components in volcanic plumes, and what are the resulting population exposures? What is the difference in the chemistry and environmental mobility of volcanic pollutants compared to other pollution sources in populated areas? And what role does climate play in controlling the dispersion and impact of volcanic plumes?

The project will focus on volcanoes with quiescent or effusive activity because these emit large amounts of gases and PM into the troposphere, and elevate their concentrations at ground level. The project will involve fieldwork and laboratory analysis of samples collected at active volcanoes; numerical modelling of volcanic plume dispersion; and GIS analysis to calculate population exposures work. Possible fieldwork locations include (but are not limited to): Iceland, Hawaii, Central America, South Pacific islands, and Reunion – we will make the choice near the start of the PhD because volcanoes are very dynamic creatures! You will get the opportunity to spend time at Iceland’s volcano observatory (Icelandic Meteorological Office, IMO) and participate in operational monitoring of volcanic activity, and hazard communication.

Note on mitigating covid19-related risk to field and lab work

We have large sample sets collected at recent eruptions (Fagradalsfjall, Iceland 2021 and Kilauea, Hawaii 2018), which have been partially analysed for chemical composition. They may be used in lieu of new samples in case of significant restrictions on new field and/or lab work.


Some volcanic hazards are well recognized and tend to receive a huge amount of media interest – for example ash-rich explosions which ground air traffic, or pyroclastic flows which bury cities. The wide-spread environmental hazard posed volcanic emissions of gas and aerosol particulate matter (PM) is generally under-researched and absent from risk management strategies. The contribution of volcanoes to the overall air and environmental pollution in populated areas is not adequately assessed, and the associated premature mortality not included in the existing estimates of deaths caused by volcanic activity.

Even when volcanoes are not erupting ash or lava, their emissions of gas and PM can last years or decades and contain various pollutants such as sulphur dioxide gas, fine particulate matter (PM2.5 and PM1) and environmentally-reactive trace elements  (Figure 1).  The environmental fate of volcanic ERT is poorly known – we don’t know how far from the volcano they spread or how long they persist in the environment.

Our recent study of the Kilauea 2018 eruption (Ilyinskaya et al., 2021) discovered that different chemical components in volcanic emissions, including ERT, have variable dispersion patterns and may ‘live’ in the atmosphere for different amounts of time. We think it is likely that the background atmospheric and climatic conditions play an important role, and that there may be significant differences between volcanoes erupting into a colder versus warmer atmosphere. Being able to understand and predict these differences is very important for assessing the resulting hazards.

Research questions and objectives

[1] How does the abundance and composition of environmentally-reactive components in a volcanic plume change from source to the far-field? You will collect and analyse a time series of samples at active volcanoes to test this.

[2] How do ambient atmospheric conditions control the dispersion of volcanic plumes and the associated air qualty and climate impacts? You will use numerical models (e.g. NAME) to simulate volcanic plumes erupted into warmer versus colder conditions.

[3] How many people are exposed to volcanic pollution? You will assess population exposures to volcanic emissions in the case study locations, and identify the more vulnerable parts  (e.g. socioeconomically deprived areas, schools, hospitals). Exposure maps may be extended to grazing livestock which is known to be affected potentially more than people.

[4] Is there a difference in environmental mobility and potential toxicity of volcanic emissions compared to other natural or anthropogenic sources?  You will compare the chemical composition of volcanic emissions to other sources (e.g. traffic, wildfires, industry).

Description of work and training provided

You will be based at the University of Leeds (Institute of Geophysics and Tectonics, Volcanology group) and you will work closely with the other supervisors at the University of Cambridge, UK Met Office and Imperial College, London. As part of the CASE studentship you will also spend time at the Iceland Met Office, the institute responsible for monitoring volcanic hazards in Iceland.

Project part 1, years 1-2*: Field sampling and laboratory analysis

You will work with samples of gas, PM and precipitation. You will collect samples at the active volcanic vent, and at different distances downwind to address research question [1]. You will also collect samples of other important local pollution sources (such as traffic, wildires, etc) to compare them to the volcanic emissions to answer research question [4]. The samples will be processed in a laboratory at Leeds and analysed for detailed chemical composition using ion chromatography and ICP-MS mass spectroscopy. You will have the opportunity to learn various methods and techniques for field measurements in volcanology, and you will be trained in clean laboratory techniques. This part will be supervised by Dr Evgenia Ilyinskaya at University of Leeds and, in the case of fieldwork in Iceland, by Gerdur Stefansdottir.

Project part 2, years 1-2*: Simulations of volcanic plume dispersion

You will learn to use a numerical model (NAME) to simulate the dispersion, atmospheric lifetime and impact(s) of volcanic plumes erupted into a colder versus warmer ambient atmosphere to address research question [2]. To begin with, you will simulate sulphur because it is the best understood volcanic pollutant in direct observations and numerical models. As you gain profiency in using the model, you can include ERT in the simulations. This part of the work will result in a new capability to simulate and forecast the dispersion and deposition of these trace pollutants in volcanic plumes. This part will be supervised by Dr Daniela Fecht at Imperial College, London.

Project part 3, years 2-3: Population exposures to different components in volcanic emissions

You will combine your results from project parts 1 and 2, and learn to use advanced GIS to assess population exposure to the different pollutants in volcanic emissions. Population exposure maps will give information about the number of people exposed, as well as the identifying the more sensitive groups of the population (e.g. socioeconomically deprived areas, schools, hospitals). This part will be supervised by Dr Daniela Fecht at Imperial College, London.

* the relative order of project parts 1 and 2 is interchangeable and may be adapted based on any covid19-related restrictions on fieldwork at the time

Other training provided

At Leeds you will have access to a broad spectrum of training workshops put on by the Faculty that include an extensive range of training workshops in numerical modelling, through to managing your degree, to preparing for your viva (http://www.emeskillstraining.leeds.ac.uk/).

Supervisor team

The project supervisors are an interdisciplinary team of experts who have had productive collaborations in the past.

Dr Evgenia Ilyinskaya (University of Leeds) specialises in direct observations of volcanic aerosols and gases. She is PI of interdisciplinary, international GCRF-funded project UNRESP aimed at building resilience to volcanic air pollution in Nicaragua. She led a NERC urgency grant on the Holuhraun eruption in Iceland 2014-2015 which discovered a previously unrecognised air pollution hazard posed by volcanic aerosols (Ilyinskaya et al., 2017). She has published 20+ peer-reviewed papers and led and/or contributed to 4 major reports on volcanic activity and hazard, including the 2015 UNISDR Global Assessment Report on volcanic risk.

Dr Anja Schmidt (University of Cambridge) is an expert in volcanic gas and aerosol modelling including the assessment of the radiative, environmental and human health impacts of volcanic eruptions. Schmidt has worked extensively on long-lasting effusive Icelandic eruptions. She advised the UK government on volcanic hazard mitigation through the Civil Contingencies Secretariat and the Scientific Advisory Group for Emergencies. She has published 40+ peer-reviewed papers and is the recipient of the 2018 EGU Arne Richter Award for Outstanding Early Career Scientists and the 2015 IAVCEI George Walker Award for Volcanology.

Dr Claire Witham (UK Met Office) is an expert on using dispersion models for simulating volcanic plumes. She is the Scientific Manager of the Volcanic and Chemical Dispersion group within the Atmospheric Dispersion and Air Quality Team in the Met Office’s Weather Science area. UKMO is home to the London Volcanic Ash Advisory Centre, which monitors and researches the dispersion of airborne volcanic emissions of gas, aerosol and ash from Iceland.

Dr Daniela Fecht (Imperial College London), lecturer in geospatial health and head of the Environmental Exposure Group within the Department of Epidemiology and Biostatistics. She is working on the development and application of geographical approaches and methods for exposure assessment and environmental health analysis making use of advanced Geographic Information Systems (GIS) methods. She is collaborating with Ilyinskaya on a study of population exposure to volcanic air pollution in Nicaragua and Iceland, including co-supervision of a successful MGeol project in 2018.

Gerdur Stefansdottir (Icelandic Meteorological Office, IMO) is the Chief Manager of Environment and Natural assets. IMO are responsible for monitoring natural and/or environmental hazards in Iceland and provide information on volcanic plume dispersion to the London Volcanic Ash Advisory Centre for aviation hazard assessments. IMO will contribute previously collected samples, and participate in acquiring new ones. Gerdur will participate in supervising on the results analysis, reporting and write-up. In the final stages of the project, IMO will advise on, and participate in, dissemination of the results to local stakeholders, such as other decision-making authorities and members of the public.

Potential for high impact outcome

This project focuses on tackling the threat of air and environmental pollution by toxic metals, by (a) yielding a better knowledge of the atmospheric spread from a significant, but under-researched natural source, and (b) providing the first assessment of this volcanic hazard by producing population exposure maps.

If successful, the resulting population exposure maps will be shared with local stakeholdersand used to engage with policy-makers and inform the public. The results of the project may be used for hazard and risk assessments for volcanic air pollution by local responsible authorities.

We anticipate the project generating at least three peer-reviewed papers in scientific journals, as well as the non-academic impacts described above.

Further reading

Ilyinskaya, E.; Mason, E.; Wieser, P. E.; Holland, L.; Liu, E. J.; Mather, T. A.; Edmonds, M.; Whitty, R. C. W.; Elias, T.; Nadeau, P. A.; Schneider, D.; McQuaid, J. B.; Allen, S. E.; Harvey, J.; Oppenheimer, C.; Kern, C.; Damby, D. Rapid Metal Pollutant Deposition from the Volcanic Plume of Kīlauea, Hawai’i. Commun. Earth Environ. 2021, 2 (1), 1–15. https://doi.org/10.1038/s43247-021-00146-2.

Schmidt, A.; Leadbetter, S.; Theys, N.; Carboni, E.; Witham, C. S.; Stevenson, J. A.; Birch, C. E.; Thordarson, T.; Turnock, S.; Barsotti, S.; Delaney, L.; Feng, W.; Grainger, R. G.; Hort, M. C.; Höskuldsson, Á.; Ialongo, I.; Ilyinskaya, E.; Jóhannsson, T.; Kenny, P.; Mather, T. A.; Richards, N. A. D.; Shepherd, J. Satellite Detection, Long-Range Transport and Air Quality Impacts of Volcanic Sulfur Dioxide from the 2014–15 Flood Lava Eruption at Bárðarbunga (Iceland). J. Geophys. Res. Atmospheres 2015, 2015JD023638. https://doi.org/10.1002/2015JD023638.

Ilyinskaya, E.; Schmidt, A.; Mather, T. A.; Pope, F. D.; Witham, C.; Baxter, P.; Jóhannsson, T.; Pfeffer, M.; Barsotti, S.; Singh, A.; Sanderson, P.; Bergsson, B.; McCormick Kilbride, B.; Donovan, A.; Peters, N.; Oppenheimer, C.; Edmonds, M. Understanding the Environmental Impacts of Large Fissure Eruptions: Aerosol and Gas Emissions from the 2014–2015 Holuhraun Eruption (Iceland). Earth Planet. Sci. Lett. 2017, 472, 309–322. https://doi.org/10.1016/j.epsl.2017.05.025.

Carlsen, H. K.; Ilyinskaya, E.; Baxter, P. J.; Schmidt, A.; Thorsteinsson, T.; Pfeffer, M. A.; Barsotti, S.; Dominici, F.; Finnbjornsdottir, R. G.; Jóhannsson, T.; Aspelund, T.; Gislason, T.; Valdimarsdóttir, U.; Briem, H.; Gudnason, T. Increased Respiratory Morbidity Associated with Exposure to a Mature Volcanic Plume from a Large Icelandic Fissure Eruption. Nature Communications 2021, 12 (1), 2161. https://doi.org/10.1038/s41467-021-22432-5.