The recent eruption of Mount Sinabung in Sumatra, Indonesia has raised little concern among Malaysians. Why bother about an erupting volcano in Indonesia? Unfortunately, due to the proximity of Sumatra to Peninsular Malaysia and wind direction , Southern states in Malaysia are expected to be shrouded by volcanic ash. The southwesterly wind direction is expected to persist until tomorrow February 6, 2014 according to the Meteorological Department. (http://www.met.gov.my)
Due to a smaller particulate size, volcanic ash can be invisible to the naked eye, in contrast to the haze from a burning forest. As a consequence of their smaller size, volcanic ash can reach into deeper structures within the lungs. So a similar advisory to those at risk, namely, those with respiratory problems, children and the elderly, should stay indoors.
Among the predominant component of volcanic ash is silica. Long term exposure to silica can cause a lung disease called silicosis. However, the needed exposure to silica is likely years, an unlikely scenario in volcanic ash exposure.
If you do have respiratory problems or eye irritation, do consult your doctors.