Experts hazy on the health risks as cloud of ash lingers overhead
High pressure has held off volcanic debris, but it may yet appear, writes Jerome Reilly
Published 18/04/2010 | 05:00
There's deep confusion over the possible health threats caused by super-fine volcanic ash, with people suffering from chronic respiratory conditions advised to stay indoors if the ash enters the lower atmosphere over Ireland and begins to cause irritation.
So far, Ireland has been protected by a band of high pressure, which has stopped the plume of ash settling over the country.
Met Eireann said: "The meteorological situation at present is that there is an anticyclone centred to the northwest of Ireland.
"The airflow is clockwise around an anticyclone.
"High pressure will continue to be the dominant influence over Ireland for some days yet, interrupted by some light rain moving southwards on Sunday."
In an update yesterday the weather service said it did not not expect any significant surface deposition of ash in the short term. "Ash and dust normally reach the surface through being washed out of the atmosphere by rain."
While Ireland is, along with the rest of northern Europe, affected by the air travel crisis caused by the eruption, we may well escape the impact of falling volcanic ash, at least for the next few days.
However, there is no indication when the eruption will end or if it will continue to increase in intensity, as it did during late Friday and Saturday.
"The activity has been quite vigorous overnight, causing the eruption column to grow," Icelandic geologist Magnus Tumi Gudmundsson told the Associated Press yesterday
"It's the magma mixing with the water that creates the explosivity. Unfortunately, there doesn't seem to be an end in sight."
The World Health Organisation (WHO) admitted "it is still unclear what exact health risks there could be from the ash cloud".
The Asthma Society of Ireland said: "It is unlikely to be noticed by people on the ground; at present there is no need for undue concern. If the situation changes, people who suffer with respiratory conditions such as asthma,chronic bronchitis and emphysema, may notice their symptoms worsening.
"This will depend on a number of factors such as concentration of particles in the ash, proportion of the particles in the ash, duration and frequency of exposure to the ash and, above all, how well your asthma is controlled."
In Britain, people are being warned to monitor their conditions closely. Minor symptoms such as a runny nose, itchy eyes or a cough may mean it is time to move indoors.
The cloud includes irritant gases and fine silica dust which, if inhaled, can reach deep within the lung, posing a danger to those with respiratory problems, WHO spokesman Daniel Epstein said in Geneva.
If people smell sulphur, rotten eggs, or a strong acidic smell when outside, they should move indoors.
"We're very concerned about it. We're studying the situation closely. However, the plume is circulating at high altitude," Mr Epstein said.
"The cloud is suspended high in the atmosphere," he added. "When the particles begin to settle to earth, that would be an increase in our health concerns."
He said that in that case, especially for people with respiratory problems and asthma, "we would recommend to stay indoors as much as possible, as in any other pollution-related event".
Volcanic ash is made up of tiny pieces of glassy sand and dust produced when explosive eruptions demolish solid rock or spray lava into the sky, where it solidifies before falling.
The respected National Geographic magazine quoted Tina Neal, a volcanologist at the Alaska Volcano Observatory in Anchorage.
She says that the particles will eventually settle out, but that this could take days or even weeks.
"At this point it doesn't seem like it's going to [accumulate] that much in continental Europe, in terms of the size of this eruption.
"But we have to watch, because if the eruption intensifies, [so may] the ash fall," she said.