Dr Claire Witham

Atmospheric Dispersion Scientist

Met Office
FitzRoy Road
Exeter, EX1 3PB
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Research Expertise


Claire currently works for the UK Met Office and is responsible for supporting the London VAAC in volcanic plume dispersion modelling. Claire Witham's research interests focus on the direct health hazards of volcanic gases and aerosols, and how these species are dispersed and deposited. She has compiled, in collaboration with other members of IVHHN, the information and guidelines on hazardous volcanic gases available on this website and conducted fieldwork to assess contemporaneous hazards. She is also interested in the historical impacts of eruptions, in particular their emissions, and has investigated the relation between the Laki Craters eruption and increased English mortality.

The ash-leachate sampling technique recommended on this website has stemmed from Claire's investigation into the removal of hazardous plume species by adsorption onto ash. Species deposited by this process can pose a serious hazard to the environment, livestock and drinking water supplies, and more work is needed to understand the mechanisms involved.

Claire has just joined the UK Met Office and is now responsible for supporting the London VAAC in volcanic plume dispersion modelling. In addition, she is working on improving general air quality forecasts and a long-term research goal is to include volcanic emissions and their chemistry in these models.


Relevant Publications

Witham, C.S., Hort, M.C., Potts, R., Servranckx, R., Husson, P., and Bonnardot, F. (2007) ‘Comparison of VAAC atmospheric dispersion models using the 1 November 2004 Grimsvotn eruption’, Meteorological Applications, 14, 27-38.

Witham, C. and Manning, A. (2007) ‘Impacts of Russian biomass burning on UK air quality’, Atmospheric Environment, 41(37), 8075-8090.

Witham, C. (2005) ‘Volcanic disasters and incidents: a new database’, Journal of Volcanology and Geothermal Research, 148, 191-233.

Witham, C. S., Oppenheimer, C. and Horwell, C. J. (2005) ‘Volcanic ash leachates: a review and recommendations for analysis methods’, Journal of Volcanology and Geothermal Research, 141, 299- 326.

Witham, C. S. and Oppenheimer, C. (2005) ‘Mortality in England during the 1783-4 Laki Craters eruption’, Bulletin of Volcanology. 67, 15-26. 

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Latest News


Download our pamphlets on preparing for ashfall and on the health hazards of ash. They are designed for mass distribution at the onset of new eruptions. They are now avaiable in English, Japanese, French Spanish, Portuguese, Swahili, Indonesian and Icelandic with Italian versions being available shortly. Please see our Pamphlets page for further infomation.





IVHHN has an article under the Guidelines tab which used to be called 'Recommended Face Masks'. This has now been updated to 'Information on face masks' and is an interim page whilst the Health Interventions in Volcanic Eruptions project investigates which types of respiratory protection are effective in protecting the general population from volcanic ash inhalation. Please note that the translations in Spanish, Japanese and Portuguese have not yet been updated.



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