It is estimated that about 25 per cent of the particles in the ash resulting from the eruption of the Eyjafjalla volcano on 14 April are less than 10 microns in size – considered more dangerous because they can penetrate deeper into the lungs, according to a news release issued by the World Health Organization (WHO).
The agency said that people with chronic respiratory conditions such as asthma, emphysema or bronchitis may be more susceptible to irritation if ash is in the lower atmosphere in high concentrations.
But as long as the ash remains in the upper atmosphere, there will not likely be an increased risk of health effects.
“Since the ash concentration may vary from country to country depending on the wind and air temperatures, our advice is to listen to local public health officials for the best guidance for individual situations,” said Maria Neira, Director of WHO’s Public Health and Environment Department.
“If people are outside and notice irritation in their throat and lungs, a runny nose or itchy eyes, they should return indoors and limit their outdoor activities,” Dr. Neira added.
WHO noted that at present the cloud is suspended high in the atmosphere and the particles have not begun to settle. When the particles do settle, they could cause an increase in health concerns.
“At that point, WHO might recommend that people stay indoors as much as possible, and if they did go outdoors, people with respiratory problems should wear a protective mask,” WHO’s Daniel Epstein told a news conference in Geneva.
Scylla Sillaayo of the UN World Meteorological Organization (WMO) told the same briefing that the ashes were a pollutant just like any other aerosol – the heavier ashes stayed closer to the source, while the lighter ones travelled for long distances before finally settling on the ground.
He added that there were volcanic ash advisory centres, and the centre in the United Kingdom was dealing with this particular problem.
While the health effects may not yet be fully known, the ash clouds are strongly affecting air traffic, with a number of European nations closing their airspace yesterday in the wake of the volcanic eruption.
“No incidents or accidents have been reported due to volcanic ash. Disruptions in air traffic, however, are being experienced in the United Kingdom and Scandinavia,” the UN International Civil Aviation Organization (ICAO) said.
The agency, based in the Canadian city of Montréal, noted that since volcanic ash is composed of very abrasive silica materials, it can damage the airframe and flight surfaces, clog different systems, scrape cockpit windows and cause the flame in jet engines to go out, constituting a serious safety hazard.
Volcanic ash can also have a serious effect on airports and airfields located downwind of a volcanic ash plume since it contaminates runways, ground equipment and aircraft parked or taxiing in the area, it added.