A new study led by IVHHN Director Claire Horwell has concluded that the ash from the Icelandic volcano Eyjafjallajökull earlier this year does not have the potential to cause long-term respiratory health problems for Icelanders. Analyses showed few physical attributes relevant to respiratory health, with the exception of only one of 14 samples.
It was discovered that ash from volcano summit eruptions in April and May this year had a low-moderate potential to exacerbate pre-existing respiratory diseases such as asthma or chronic bronchitis during the period of ash fall. The potential for the development of long-term lung problems from the exposure to the ash during the eruption or afterwards from resuspension of the ash deposits was low.
Average outdoor air concentrations in the ashfall area could be expected to regularly exceed World Health Organisation (WHO) 24-hour guideline levels for particles in the ambient air until the ash is incorporated into the environment with repeated rainfall. But it was concluded that persistence of deposited ash once integrated into the soil and wider environment would not present a significant silicosis hazard to, for example, outdoor workers, since the crystalline silica content is negligible.
The study was led by Durham University's Institute of Hazard, Risk & Resilience, where Dr Horwell is based. Using 14 different samples from across Iceland, it was found that the ash contained a significant amount of very fine-grained particles which could irritate the airways of susceptible people who already have asthma or chronic bronchitis. But in vitro experiments suggested that the risk of the ash triggering acute pulmonary inflammation at ambient levels of exposure is low.
Dr Horwell says: "The ash from the Eyjafjallajökull volcano was quite fine-grained, meaning it could get into the lungs and perhaps cause irritation. Then we looked for other physical attributes of the ash that could possibly trigger more serious problems in the lungs. Fortunately, the ash displayed very low amounts of these attributes.
"For example, crystalline silica could potentially be a problem in volcanic ash; it's known to be toxic in other circumstances. The ash from the volcano contained virtually none of this, which is good news.”
"In general, the ash really displayed low toxic properties for all of the different experiments we did, with the exception of only one sample which wasn't exposed to the elements before collection.”
Her colleague Dr Peter Baxter, the leading medical expert on volcanic health hazards, based at the University of Cambridge, said:
"The results on the ash are reassuring, but the risk to exposed people of developing acute respiratory symptoms or having pre-existing lung problems worsened would need to be evaluated in a survey of the communities in the ash fall areas."