Evidence on the Potential Health Impacts of Volcanic Ash

Synopsis

Background

In recognition of the potential risk to the United Kingdom (UK) and Republic of Ireland (ROI), the Health Protection Agency together with national and international partners has set up a programme of work by which to ensure an effective response to any future volcanic eruptions.

Methods

A literature review on the potential health impacts of ash was carried out of clinical and epidemiological studies of affected populations worldwide. This was supplemented by reviews of the toxicological evidence on volcanic ash and of physicochemical parameters on which inferences about potential health effects may be based. Expert opinion was sought in areas of uncertainty.

Results

A number of studies, though not all, showed that in the short-term volcanic ash may cause superficial effects such as irritation of the eyes, nose, throat and skin. Effects on breathing may include exacerbations of asthma and wheeze. Development of silicosis as a long-term effect of exposure to volcanic ash rich in crystalline silica is a biologically plausible consequence but so far no cases have been reported. In terms of physicochemical characteristics and toxicology, volcanic ash samples are very heterogeneous. There is some indication that volcanic ash is less toxic compared with particulates in ambient air; however, studies in this area are very limited.

Recommendations

For Public Health Action

• Risk assessors may need to consider a PRECAUTIONARY APPROACH whereby volcanic ash is considered EQUITOXIC to particulates in ambient urban air.
• Given uncertainties in evidence base, this position needs to be regularly reviewed and public health guidance should be responsive to real-time health intelligence, data from the UK air quality network, and any modelling data available by way of early alerting as to the characteristics of likely ashfall on the UK from an eruption.

For Further Research

• Direct comparisons need to be undertaken of volcanic ash particles compared with particles in ambient urban air.
• Consider physicochemical analysis of archived samples of volcanic ash from Iceland.
• Consider further epidemiological studies.

Last reviewed: 20 November 2012