|Professor of Geohealth in the Department of Earth Sciences||Rm 248||42253|
|Management Board Member in Institute of Hazard, Risk and Resilience||+44 (0) 191 33 42253|
|Fellow of the Wolfson Research Institute for Health and Wellbeing||+44 (0) 191 33 42253|
2019 - present
IHRR & Department of Earth Sciences, Durham University, UK
|2014 - present||Honorary Professor|| |
UK Health & Security Agency (formerly PHE/HPA)
|2012 - 2019||Lecturer/Sr Lecturer/Reader/Assoc Prof||IHRR & Department of Earth Sciences, Durham University, UK|
|2012 - 2016||Co-Director||IHRR, Durham University, UK|
|2011 - present||Fellow||Wolfson Institute for Health & Wellbeing, Durham University, UK|
|2003 - present||Director||International Volcanic Health Hazard Network|
|2007 - 2012||RCUK & NERC Fellow||IHRR & Department of Earth Sciences, Durham University, UK|
|2005 - 2007||NERC Fellow||Department of Earth Science, University of Cambridge, UK|
|2003 - 2005||Leverhulme Trust PDRA||School of Earth Science, University of Bristol, UK|
|1999 - 2002||NERC CASE PhD student||School of Earth Science, University of Bristol, UK|
Career Research Highlights
I am founder/director of the International Volcanic Health Hazard Network, the umbrella organisation for volcanic health research and dissemination. I have acted as advisor to the World Health Organization, Public Health England and the UK Cabinet Office regarding the respiratory health hazards of volcanic ash. I also work with government and non-governmental agencies, around the world, helping them to prepare the health response for future volcanic eruptions, and responding during volcanic crises.
My research interest is in understanding the health hazards of natural and industrial mineral dusts and in helping communities to prepare for, and protect themselves from volcanic emissions and other particulate pollution crises. My research is split into several, interdisciplinary strands, which are conducted with multiple UK and international collaborators across the natural, social and medical sciences:
Are mineral particles harmful when inhaled?
i) Physicochemical analysis of particles: use of mineralogical and geochemical techniques to assess respiratory hazard. These are combined with my students' and collaborators’ toxicological assessements to determine potential respiratory hazard of volcanic ash, combusted biomass, diatomaceous earth, desert dust and coal dust.
ii) Fundamental questions surrounding the ‘structure-toxicity’ relationship of mineral particles and interacting elements (e.g. anthropogenic pollution), and the variable toxicity of crystalline silica are also addressed through mineralogical, geochemical and toxicological analyses. Petrological techniques are also employed to understand how crystalline silica forms in volcanic systems (paricularly lava domes).
iii) Exposure assessments to airborne particles is a key part of determining potential hazard. My group conducts air quality assessments using state-of-the-art portable aerosol monitors.
How can communities prepare for, and protect themselves from, airborne particulate crises?
iv) Working with GOs, NGOs and behavioural psychologists and social anthropologists, we conduct social research within local communities to understand their lifestyles, cultural contexts, and how their risk perceptions influence their protective behaviours. We also investigate how their current protective strategies relate to official advice.
v) We assess the effectiveness of community use of respiratory protection (from industry-certified RPE to cloth face-coverings) through laboratory tests and field trials, in collaboration with exposure scientists and PPE experts at the Institute of Occupational Medicine.
vi) With social learning experts, we work with communities and local authorities to co-develop evidence-based printable and audio visual informational products which inform people on the most effective protection strategies for exposure reduction to airborne pollutants. Our products are available at www.ivhhn.org.
vii) We evaluate the ethical and legal aspects of agencies distributing or recommending different forms of respiratory protection for community use.
Committee and Society Service
2022 - 2024 - Member of the Royal Society's Research Grants Board
2020 - 2022 - Member of the European Geosciences Union's Plinius Medal Committee
2017- 2020- President (and former President-elect and Founding Leader); GeoHealth Section, American Geophysical Union
2017 - 2020 - Council Member, American Geophysical Union
2015 - present - Member; Scientific Advisory Group for Emergencies (SAGE) for volcanic eruptions, UK Government
2014 – 2017— Chair, Nominations & Awards Committee; International Medical Geology Association
2013 – 2015— Member; Expert Advisory Group for Risk H55, UK Government Cabinet Office
2011 – present — Member; Public Health England's expert panel for future ashfall affecting the UK
2011 – present — Member of Scientific Steering Committee and Project Partner; Global Volcano Model
2011 – 2014 — Chair, Education Committee; International Medical Geology Association
2010 – 2011 — Member; Scientific Advisory Committee for Iceland Eruptions; World Health Organization
2005 – 2007 — Representative for Health for the ICSU 5 GeoUnions Initiative; International Union of Geodesy and Geophysics
2007 – 2012 — Research Councils UK: Fellow
2005 – 2011 — NERC Postdoctoral Fellow
- Institute of Hazard, Risk & Resilience (IHRR)
- Volcanology Research Group
- 2021: 2021-2024: FACE-UP - Factors Affecting Childhood Exposures to Urban Particulates, UKRI MRC (GCRF)
- 2015: 2015-2019 HIVE: A new evidence base for respiratory Health Interventions in Volcanic Eruption crises, ELRHA
- 2007: 2005-2012: NERC Fellowship - Natural Mineral Dusts and Their Respiratory Health Hazard
- 2006: 2007-2012: IHRR UKRI Fellowship (Volcanic Hazards), EPSRC £125,000.
Chapter in book
- Baxter, P.J. & Horwell, C.J. (2015). Impacts of eruptions on human health. In The Encyclopedia of Volcanoes. Sigurdsson, H., Houghton, B., McNutt, S., Rymer, H. & Stix, J. Elsevier.
- Horwell, C.J., Baxter, P.J. & Kamanyire, R. (2015). Health Impacts of Volcanic Eruptions. In Global Volcanic Hazards and Risk. Loughlin, S.C., Vye-Brown, C., Sparks, R.S.J., Brown S.K. & Jenkins, S.F. Cambridge University Press.
- Weinstein, P., Horwell, C.J. & Cook, A. (2013). Volcanic emissions and health. In Essentials of Medical Geology. Selinus, O., Alloway, B., Centeno, J.A., Finkelman, R.B., Fuge, R., Lindh, U. & Smedley P. Springer. 805.
- Derbyshire, E., Horwell, C.J., Tetley, T. & Jones, T.P. (2011). Airborne Paricles. In Pollutants, human health and the environment: Introduction for environmental scientists and health professionals. Plant, J.A., Ragnarsdottir, K.V. & Vouvoulis, N. Wiley. 255-286.
- Schwartz-Marin, E., Merli, C., Rachmawati, L., Horwell, C. J. & Nugroho, F. (2022). Merapi multiple: Protection around Yogyakarta’s celebrity volcano through masks, dreams, and seismographs. History and Anthropology 33(5): 588-610.
- Stewart, C., Damby, D. E., Horwell, C. J., Elias, T., Ilyinskaya, E., Tomašek, I., Longo, B. M., Schmidt, A., Carlsen, H. K., Mason, E., Baxter, P. J., Cronin, S. & Witham, C. (2022). Volcanic air pollution and human health: recent advances and future directions. Bulletin of Volcanology 84(1): 11.
- Covey, J., Dominelli, L., Horwell, C. J., Rachmawati, L., Martin-del Pozzo, A. L., Armienta, M. A., Nugroho, F. & Ogawa, R. (2021). Carers' perceptions of harm and the protective measures taken to safeguard children's health against inhalation of volcanic ash: A comparative study across Indonesia, Japan and Mexico. International Journal of Disaster Risk Reduction 59: 102194.
- Tomašek, I., Damby, D. E., Andronico, D., Baxter, P. J., Boonen, I., Claeys, P., Denison, M. S., Horwell, C. J., Kervyn, M. Kueppers, U., Romanias, M. N. & Elskens, M. (2021). Assessing the biological reactivity of organic compounds on volcanic ash: implications for human health hazard. Bulletin of Volcanology 83(5): 30.
- Tomašek, I., Damby, D. E., Stewart, C., Horwell, C. J., Plumlee, G., Ottley, C. J., Delmelle, P., Morman, S., Yazidi, S. E. L., Claeys, P., Kervyn, M., Elskens, M. & Leermakers, M. (2021). Development of a simulated lung fluid leaching method to assess the release of potentially toxic elements from volcanic ash. Chemosphere 278: 130303.
- McDonald, F & Horwell, C.J. (2021). Air Pollution Disasters: Liability Issues in Negligence Associated With the Provision of Personal Protective Interventions (Facemasks). Disaster Medicine and Public Health Preparedness 15(3): 367-373.
- Mueller, W., Cowie, H., Horwell, C. J., Hurley, F. & Baxter, P. J. (2020). Health Impact Assessment of volcanic ash inhalation: A comparison with outdoor air pollution methods. GeoHealth 4(7): e2020GH000256.
- Smart, N.R., Horwell, C.J., Smart, T.S. & Galea, K.S (2020). Assessment of the Wearability of Facemasks against Air Pollution in Primary School-Aged Children in London. International Journal of Environmental Research and Public Health 17(11): 3935.
- Mueller, W., Cowie, H., Horwell, C. J., Baxter, P. J., McElvenny, D., Booth, M., Cherrie, J. W., Cullinan, P., Jarvis, D. Ugarte, C. & Inoue, H. (2020). Standardized epidemiological protocols for populations affected by volcanic eruptions. Bulletin of the World Health Organization 98(5): 362-364.
- McDonald, F., Horwell, C.J., Wecker, R., Dominelli, L., Loh, M., Kamanyire, R. & Ugarte, C. (2020). Facemask use for community protection from air pollution disasters: An ethical overview and framework to guide agency decision making. International Journal of Disaster Risk Reduction 43: 101376.
- Stewart, C., Damby, D.E., Tomašek, I., Horwell, C.J., Plumlee, G.S., Armienta, M.A., Hinojosa, M.G.R., Appleby, M., Delmelle, P., Cronin, S., Ottley, C.J., Oppenheimer, C. & Morman, S. (2020). Assessment of leachable elements in volcanic ashfall: A review and evaluation of a standardized protocol for ash hazard characterization. Journal of Volcanology and Geothermal Research 392: 106756.
- Covey, J., Horwell, C.J., Ogawa, R., Baba, T., Nishimura, S., Hagino, M. & Merli, C. (2020). Community perceptions of protective practices to prevent ash exposures around Sakurajima volcano, Japan. International Journal of Disaster Risk Reduction 101525.
- Tomašek, I., Damby, D.E., Horwell, C.J., Ayris, P.M., Delmelle, P., Ottley, C.J., Cubillas, P., Casas, A.S., Bisig, C., Petri-Fink, A., Dingwell, D.B., Clift, M.J.D., Drasler, B. & Rothen-Rutishauser, B. (2019). Assessment of the potential for in-plume sulphur dioxide gas-ash interactions to influence the respiratory toxicity of volcanic ash. Environmental Research 179(Part A): 108798.
- Pavan, C., Delle Piane, M., Gullo, M., Filippi, F., Fubini, B., Hoet, P., Horwell, C.J., Huaux, F., Lison, D., Lo Giudice, C., Martra, G., Montfort, E., Schins, R., Sulpizi, M., Wegner, K., Wyart-Remy, M., Ziemann, C. & Turci, F. (2019). The puzzling issue of silica toxicity: are silanols bridging the gaps between surface states and pathogenicity? Particle and Fibre Toxicology 16(1): 32.
- Covey, J., Horwell, C.J., Rachmawati, L., Ogawa, R., Martin-del Pozzo, A.L., Armienta, M.A., Nugroho, F. & Dominelli, L (2019). Factors motivating the use of respiratory protection against volcanic ashfall a comparative analysis of communities in Japan, Indonesia and Mexico. International Journal of Disaster Risk Reduction 35: 101066.
- Horwell, C.J., Ferdiwijaya, D., Wahyudi, T. & Dominelli, L. (2019). Use of respiratory protection in Yogyakarta during the 2014 eruption of Kelud, Indonesia: Community and agency perspectives. Journal of Volcanology and Geothermal Research 382: 92-102.
- Galea, K.S., Covey, J., Mutia Timur, S., Horwell, C.J., Nugroho, F. & Mueller, W. (2018). Health Interventions in Volcanic Eruptions—Community Wearability Assessment of Respiratory Protection against Volcanic Ash from Mt Sinabung, Indonesia. International Journal of Environmental Research and Public Health 15(11): 2359.
- Mueller, W., Horwell, C.J., Apsley, A., Steinle, S., McPherson, S., Cherrie, J.W. & Galea, K.S. (2018). The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation. Part I: Filtration efficiency tests. International Journal of Hygiene and Environmental Health 221(6): 967-976.
- Cherrie, J.W., Apsley, A., Cowie, H., Steinle, S., Mueller, W., Lin, C., Horwell, C.J., Sleeuwenhoek, A. & Loh, M. (2018). Effectiveness of face masks used to protect Beijing residents against particulate air pollution. Occupational and Environmental Medicine 75(6): 446-452.
- Steinle, S, Sleeuwenhoek, A, Mueller, W, Horwell, CJ, Apsley, A, Davis, A, Cherrie, JW & Galea, KS (2018). The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation; Part II: Total inward leakage tests. International Journal of Hygiene and Environmental Health 221(6): 977-984.
- Tomašek, I., Horwell, C.J., Bisig, C., Damby, D.E., Comte, P., Czerwinskid, J., Petri-Fink, A., Clift, M.J.D., Drasler, B. & Rothen-Rutishauser, B. (2018). Respiratory hazard assessment of combined exposure to complete gasoline exhaust and respirable volcanic ash in a multicellular human lung model at the air-liquid interface. Environmental Pollution 238: 977-987.
- Damby, D.E., Horwell, C.J., Baxter, P.J., Kueppers, U., Schnurr, M., Dingwell, D.B. & Duewell, P. (2018). Volcanic Ash Activates the NLRP3 Inflammasome in Murine and Human Macrophages. Frontiers in Immunology 8: 2000.
- Nattrass, C., Horwell, C.J., Damby, D.E., Brown, D. & Stone, V. (2017). The effect of aluminium and sodium impurities on the in vitro toxicity and pro-inflammatory potential of cristobalite. Environmental Research 159: 164-175.
- Damby, D.E., Horwell, C.J., Larsen, G., Thordarson, T., Tomatis, M., Fubini, B. & Donaldson, K. (2017). Assessment of the potential respiratory hazard of volcanic ash from future Icelandic eruptions: a study of archived basaltic to rhyolitic ash samples. Environmental Health 16: 98.
- Horwell, C. J., Sargent, P., Andronico, D., Lo Castro, M. D., Tomatis, M., Hillman, S. E., Michnowicz, S. A. K. & Fubini, B. (2017). The iron-catalysed surface reactivity and health-pertinent physical characteristics of explosive volcanic ash from Mt. Etna, Italy. Journal of Applied Volcanology 6(1): 12.
- Le Blond, J.S., Woskie, S., Horwell, C.J. & Williamson, B.J. (2017). Particulate matter produced during commercial sugarcane harvesting and processing: a respiratory health hazard? Atmospheric Environment 149: 34-46.
- Tomašek, I., Horwell, C.J., Damby, D.E., Barošová, H., Geers, C., Petri-Fink, A., Rothen-Rutishauser, B. & Clift, M.J.D. (2016). Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model. Particle and Fibre Toxicology 13(1): 67.
- Damby, D.E., Murphy, F.A., Horwell, C.J., Raftis, J. & Donaldson, K. (2016). The in vitro respiratory toxicity of cristobalite-bearing volcanic ash. Environmental Research 145: 74-84.
- Nattrass, C., Horwell, C.J., Damby, D.E., Kermanizadeh, A. Brown, D.M. & Stone, V. (2015). The global variability of diatomaceous earth toxicity: a physicochemical and in vitro investigation. Journal of Occupational Medicine and Toxicology 10: 23.
- Horwell, C.J., Damby, D.E. & Hillier, S. (2015). Respirable volcanic ash is distinct mineralogically, physicochemically and toxicologically from soils originating from weathered volcanic products. A comment on Cervini-Silva et al. (2014) “Lipid peroxidation and cytotoxicity induced by respirable volcanic ash”. Journal of Hazardous Materials 285: 366-367.
- Samarasundera, E, Hansell, A, Leibovici, D, Horwell, C.J., Anand, S & Oppenheimer, C (2014). Geological hazards: from early warning systems to public health toolkits. Health & Place 30: 116-119.
- Damby, D.E., Llewellin, E.W., Horwell, C.J., Williamson, B.J., Najorka, J., Cressey, G. & Carpenter, M.A. (2014). The α-β phase transition in volcanic cristobalite. Journal of Applied Crystallography 47(4): 1205-1215.
- Horwell, C.J., Hillman, S.E., Cole, P.D., Loughlin, S.C., Llewellin, E.W., Damby, D.E. & Christopher, T. (2014). Controls on variations in cristobalite abundance in ash generated by the Soufrière Hills volcano, Montserrat in the period 1997-2010. Memoir of the Geological Society of London 39: 399-406.
- Baxter, P J, Searl, A, Cowie, H A, Jarvis, D & Horwell, C J (2014). Evaluating the respiratory health risks of volcanic ash at the eruption of the Soufrière Hills Volcano, Montserrat, 1995-2010. Memoir of the Geological Society of London 39(22).
- Stevenson, J.A., Loughlin, S.C., Font, A., Fuller, G.W., MacLeod, A., Oliver, I.W., Jackson, B., Horwell, C.J., Thordarson, T. & Dawson, I. (2013). UK monitoring and deposition of tephra from the May 2011 eruption of Grímsvötn, Iceland. Journal of Applied Volcanology 2: 3.
- Horwell, C.J., Williamson, B.J., Llewellin, E.W., Damby, D.E. & Le Blond, J.S. (2013). Nature and formation of cristobalite at the Soufriere Hills Volcano, Monserrat: implications for the petrology and stability of silicic volcanic domes. Bulletin of Volcanology 75: 696.
- Damby, D.E., Horwell, C.J. Baxter, P.J., Delmelle, P., Donaldson, K., Dunster, C., Fubini, B., Murphy, F.A., Nattrass, C., Sweeney,S., Tetley, T.D. & Tomatis, M. (2013). The respiratory health hazard of tephra from the 2010 Centennial eruption of Merapi with implications for occupational mining of deposits. Journal of Volcanology and Geothermal Research 261: 376-387.
- Horwell, C J, Baxter, P J, Hillman, S E, Calkins, J A, Damby, D E, Delmelle, P, Donaldson, K, Dunster, C, Fubini, B, Hoskuldsson, A, Kelly, F J, Larsen, G, Le Blond, J S, Livi, K J T, Mendis, B, Murphy, F, Nattrass, C, Sweeney, S, Tetley, T D, Thordarson, T & Tomatis, M (2013). Physicochemical and toxicological profiling of ash from the 2010 and 2011 eruptions of Eyjafjallajökull and Grímsvötn volcanoes, Iceland using a rapid respiratory hazard assessment protocol. Environmental Research 127: 63-73.
- Hillman, S.E., Horwell, C.J., Densmore, A.L., Damby, D.E., Fubini, B., Ishimine, Y. & Tomatis, M. (2012). Sakurajima volcano: a physico-chemical study of the health consequences of long-term exposure to volcanic ash. Bulletin of Volcanology 74(4): 913-930.
- Horwell, C.J., Williamson, B.J., Donaldson, K., Le Blond, J.S., Damby, D.E. & Bowen, L. (2012). The structure of volcanic cristobalite in relation to its toxicity; relevance for the variable crystalline silica hazard. Particle and Fibre Toxicology 9(November 2012 ): 44.
- Le Blond, J S, Tomatis, M, Horwell, C J, Dunster, C, Murphy, F, Corazzari, I, Grendene, F, Turci, F, Gazzano, E, Ghigo, D, Williamson, B J, Oppenheimer, C & Fubini, B (2012). The surface reactivity and implied toxicity of ash produced from sugarcane burning. Environmental Toxicology 29(5): 503-516.
- Durant AJ, Bonadonna C & Horwell CJ (2010). Atmospheric and environmental impacts of volcanic particulates. Elements 6(4): 235-240.
- Le Blond J.S., Horwell C.J., Williamson B.J. & Oppenheimer C. (2010). Generation of crystalline silica from sugarcane burning. Journal of Environmental Monitoring 12(7): 1459-1470.
- Le Blond, J.S., Horwell, C.J., Baxter, P.J., Michnowicz, S.A.K., Tomatis, M., Fubini, B., Delmelle P, Dunster C & Patia H (2010). Mineralogical analyses and in vitro screening tests for the rapid evaluation of the health hazard of volcanic ash at Rabaul volcano, Papua New Guinea. Bulletin of Volcanology 72(9): 1077-1092.
- Horwell CJ, Stannett GW, Andronico D, Bertagnini A, Fenoglio I, Fubini B, Le Blond JS & Williamson BJ (2010). A physico-chemical assessment of the health hazard of Mt. Vesuvius volcanic ash. Journal of Volcanology and Geothermal Research 191(3-4): 222-232.
- Williamson, B.J., Di Muro A., Horwell C.J., Spieler O. & Llewellin E.W. (2010). Injection of vesicular magma into an andesitic dome at the effusive–explosive transition. Earth and Planetary Science Letters 295(1-2): 83-90.
- Horwell CJ, Le Blond JS, Michnowicz SAK & Cressey G (2010). Cristobalite in a rhyolitic lava dome: Evolution of ash hazard. Bulletin of Volcanology 72(2): 249-253.
- Le Blond, J.S., Cressey, G, Horwell, C.J. & Williamson, B.W. (2009). A rapid method for quantifying single mineral phases in heterogeneous natural dusts using X-ray diffraction. Powder Diffraction 24: 17-23.
- Martin, R.S., Mather, T.A., Pyle, D.M., Power, M., Tsanev, V.I., Oppenheimer, C., Allen, A.G., Horwell, C.J. & Ward E.P.W. (2009). Size distributions of fine silicate and other particles in Masaya's volcanic plume. Journal of Geophysical Research – Atmospheres 114: D09217.
- Martin, R S. Mather, T A., Pyle, D M., Power, M., Allen, A G., Aiuppa, A., Horwell, C J. & Ward, E P W. (2008). Composition-resolved size distributions of volcanic aerosols in the Mt. Etna plumes. Journal of Geophysical Research - Atmospheres 113: D17211.
- Le Blond, J S., Williamson, B J., Horwell, C J., Monro, A K., Kirk, C A. & Oppenheimer, C. (2008). Production of potentially hazardous respirable silica airborne particulate from the burning of sugarcane. Atmospheric Environment 42(22): 5558-5568.
- Horwell, C.J. (2007). Grain-size analysis of volcanic ash for the rapid assessment of respiratory health hazard. Journal of Environmental Monitoring 9: 1107-1115.
- Horwell, C.J., Fenoglio, I. & Fubini, B. (2007). Iron-induced hydroxyl radical generation from basaltic volcanic ash. Earth and Planetary Science Letters 261(3-4): 662-669.
- Hansell, A., Horwell, C.J. & Oppenheimer, C. (2006). The health hazards of volcanoes and geothermal areas. Occupational and Environmental Medicine 63(2): 149-156.
- Stewart, C., Johnston, D.M., Leonard, G., Horwell, C.J., Thordarsson, T. & Cronin, S. (2006). Contamination of water supplies by volcanic ashfall: A literature review and simple impact modelling. Journal of Volcanology and Geothermal Research 158(3-4): 296-306.
- Horwell, C.J. & Baxter, P.J. (2006). The respiratory health hazards of volcanic ash: a review for volcanic risk mitigation. Bulletin of Volcanology 69(1): 1-24.
- Horwell, C.J., Patterson, J.E., Gamble, J.A. & Allen, A.G. (2005). Monitoring and mapping of hydrogen sulphide emissions across an active geothermal field: Rotorua, New Zealand. Journal of Volcanology and Geothermal Research 139: 259-269.
- Witham, C.S., Oppenheimer, C. & Horwell, C.J. (2005). Volcanic ash-leachates: a review and recommendations for sampling methods. Journal of Volcanology and Geothermal Research 141(3-4): 299-326.
- Horwell, C.J., Allen, A.G., Mather, T.A. & Patterson, J.E. (2004). Evaluation of a novel passive sampling technique for monitoring volcanogenic hydrogen sulphide. Journal of Environmental Monitoring 6(7): 630-635.
- Horwell, C.J., Fenoglio, I., Ragnarsdottir, K.V., Sparks, R.S.J. & Fubini, B. (2003). Surface reactivity of volcanic ash from the eruption of Soufrière Hills volcano, Monserrat, West Indies with implications for health hazards. Environmental Research 93(2): 202-215.
- Horwell, C.J., Sparks, R.S.J., Brewer, T.S., Llewellin, E.W. & Williamson, B.J. (2003). Characterization of respirable volcanic ash from the Soufrière Hills volcano, Montserrat, with implications for human health hazards. Bulletin of Volcanology 65(5): 346-362.
- Horwell, C.J., Braña, L.P., Sparks, R.S.J., Murphy, M.D. & Hards, V.L. (2001). A geochemical investigation of fragmentation and physical fractionation in pyroclastic flows from from the Soufriere Hills volcano, Montserrat. Journal of Volcanology and Geothermal Research 109(4): 247-262.
- Jones, A.P. Bentham, G. & Horwell, C. (1999). Health service accessibility and deaths from asthma. International Journal of Epidemiology 28: 101-105.