Volcanoes can be bad for your health long after they have finished erupting. A research team studying the aftermath of the Soufriere Hills Volcano in Montserrat, which included Professor Ray Dupree from the University of Warwick's Department of Physics, has found that the aftermath of that volcano includes a great deal of volcanic ash particles that are just the right size to cause silicosis (a scarring disease of the lungs) and which may also be carcinogenic.
The Montserrat volcano was characterised by pyroclastic flows (a cloud of super heated matter) formed by a lava dome collapse within the volcano. This generates between three and fours times as much finer ash than volcanoes that have more rapid and explosive eruptions. The problem is made even worse in volcanoes such as the Montserrat one as the pyroclastic flows can produce giant plumes (up to several kilometres in height) of fine ash. Ash falls from such a volcano can persist for months or even years.
The Soufriere Hills volcano began erupting on 18th July 1995 but airborne ash concentrations in the area have been continually monitored since 1997, and have often detected concentrations of ash that have exceeded the UK's air quality standard.
The researchers also found that a significant amount of the Montserrat volcanic ash was under 3 nanometres in diameter (small enough to deposit deep in the lung). The ash also contained large amounts of cristobalite, a form of silica and a known hazard which can cause silicosis.
Note for editors -- The research team included researchers from the University of Warwick, Bristol University, Cambridge University, the British Geological Survey, and the Institute of Occupational Medicine in Edinburgh.