PAHO Panel on Health Impact of Volcanic Eruptions


Studies of the respiratory health effects of different types of volcanic ash have been undertaken only in the last 40 years, and mostly since the eruption of Mt. St. Helens in 1980. This review of all published clinical, epidemiological and toxicological studies, and other work known to the authors up to and including 2005, highlights the sparseness of studies on acute health effects after eruptions and the complexity of evaluating the long-term health risk (silicosis, non-specific pneumoconiosis and chronic obstructive pulmonary disease) in populations from prolonged exposure to ash due to persistent eruptive activity.

pdf  The respiratory health hazards of volcanic ash: a review for volcanic risk mitigation

Claire J. Horwell, Peter J. Baxter.


Frequent ash fallout from long-lived eruptions (with active phases greater than 5 years) may lead to local populations experiencing unacceptably high cumulative exposures to respirable particulate matter. Ash from Montserrat has been shown to contain significant levels of cristobalite and other reactive agents that are associated with an increased risk of developing pneumoconiosis (including silicosis) and other long-term health problems. In this paper it is presented a method for calculating the long-term cumulative exposure to cristobalite from volcanic ash by Monte Carlo simulation. Code has been written to generate synthetic time series for volcanic activity, rainfall, ash deposition and erosion to give daily ash deposit values and cristobalite fraction at a range of locations.

pdf  Long term exposure to respirable volcanic ash on Montserrat: a time series simulation

T. K. Hincks, W. P. Aspinall, P. J. Baxter, A. Searl, R. S. J. Sparks and G.Woo.


The management and outcomes of the volcanic crisis on Montserrat, which began with the onset of activity at the Soufrière Hills Volcano (SHV) on 18 July 1995, might have been very different without the scientific precedents set by the Mount St Helens eruption, USA, on 18 May 1980, and the research advances that followed. This narrative is intended to show the steps taken by health scientists in response to the unfolding developments at the volcano to characterize the hazard presented by the volcanic ash and to devise mitigation measures to prevent the development of irreversible lung disease in the island population. Initial assessments of the health risk for silicosis were deterministic and based on industry exposure limits derived from published epidemiological and clinical studies of workers exposed to dusts containing free crystalline silica. 

pdf  Evaluating the respiratory health risks of volcanic ash at the eruption of the Soufrière Hills Volcano, Montserrat, 1995 to 2010

 P. J. Baxter, A. S. Searl, H. A. Cowie, D. Jarvis and C. J. Horwell


In July 1995 the volcano on the West Indian island of Montserrat erupted after being inactive for several hundred years. Since then, clouds of ash have been released intermittently from the
volcano. Some of this ash is <10 m in diameter and therefore respirable. Concerns were raised that the particles might cause respiratory problems. Volcanic ash emissions adversely affected the respiratory health of Montserrat children. The findings in this document emphasize the need to limit exposures of children to volcanic ash and ensure the appropriate management of respiratory symptoms.

pdf Volcanic ash and respiratory symptoms in children on the island of Montserrat, British West Indies

L Forbes, D Jarvis, J Potts and P J Baxter. 

ArticlePublicationIconThis study documented elevated rates of emergency room (ER) visits for acute upper and lower respiratory infections and asthma-related conditions in the children of Quito, Ecuador associated with the eruption of Guagua Pichincha in April of 2000.

pdf  Emergency room visits for respiratory conditions in children increased after Guagua Pichincha volcanic eruptions in April 2000 in Quito, Ecuador Observational Study: Time Series Analysis

Elena N Naumova, Hugo Yepes, Jeffrey K Griffiths, Fernando Sempértegui, Gauri Khurana, Jyotsna S Jagai, Edgar Játiva and Bertha Estrella.

ArticlePublicationIconOfficial response to explosive volcano hazards usually involves evacuation of local inhabitants to safe shelters. Enforcement is often difficult and problems can be exacerbated when major eruptions do not ensue. Families are deprived of livelihoods and pressure to return to hazardous areas builds. Concomitantly, prevailing socio-economic and political conditions limit activities and can influence vulnerability. This paper addresses these issues, examining an ongoing volcano hazard (Tungurahua) in Ecuador where contextual realities significantly constrain responses. Fieldwork involved interviewing government officials, selecting focus groups and conducting surveys of evacuees in four locations: a temporary shelter, a permanent resettlement, with returnees and with a control group. Differences in perceptions of risk and health conditions and in the potential for economic recovery were found among groups with different evacuation experiences. The long-term goal is to develop a model of community resilience in long-term stress environments.

pdf  Community resilience and volcano hazard: the eruption of Tungurahua and evacuation of the faldas in Ecuador

Graham. A. Tobin and Linda M. Whiteford

ArticlePublicationIconThis publication addresses how atmospheric constituents and events impact human health, and how environmental monitoring has aided our understanding of them. The principal focus is on planetary processes (volcanoes and desert dust storms); a secondary theme addresses surface emissions from anthropogenic sources.

pdf  Air quality and human health

D.W. Griffin and  E.N. Naumova with J.C. McEntee, D. Castronovo, J.L.

Durant, M.B. Lyles, F.S Faruque and D.J. Lary

ArticlePublicationIconLa presente publicación recoge las percepciones y experiencias recopiladas de los procesos eruptivos de los volcanes Pichincha y Tungurahua, que por una extraña coincidencia iniciaron su actividad a mediados del año 1999. Consideraciones químicas, epidemiológicas y clínicas han permitido dimensionar como, la ceniza volcánica puede convertirse en un nuevo agente de contaminación química, el análisis comparativo de la composición química de la ceniza volcánica de los dos volcanes y su influencia sobre la calidad de aire de la ciudad de Quito y de sus zonas aledañas; así como el impacto en lo económico, social y humano que los masivos desplazamientos humanos han inferido sobre las poblaciones afectadas, permiten avizorar un nuevo agente de contaminación química

pdf  Ceniza Volcánica: un nuevo agente de contaminación química

 Dr. Marco Álvarez y Dr. José Avilés.

ArticlePublicationIconThe August 1991 eruption of Mt. Hudson (Chile) deposited ash across southern Argentina and contributed to the deaths of thousands of grazing sheep. Early ash analysis revealed high levels of fluoride, a potential ash constituent toxic to humans and animals. In order to evaluate fluorosis as the cause of sheep deaths and to examine the possibility that similar ash and airborne toxins could also have an effect on the human population, we conducted an investigation that included health provider interviews, hospital record review, physical examination of sheep, determination of sheep urine fluoride levels, and complete constituent analysis of ash samples collected at proscribed distances from the volcano. Ash deposited farthest from the volcano had highest fluoride levels; all fluoride measurements were normal after rainfall. There were no signs or symptoms of fluorosis observed in sheep or humans. Sheep deaths resulted from physical, rather than chemical properties of the ash.

pdf  Evaluating a Fluorosis Hazard after a Volcanic Eruption (2.65 MB)
Professor Erick K. Noji, M.D.