Volcanic Ash From Iceland May Have Health Consequences
By Fran Lowry
Medscape Medical News
April 16, 2010 — The World Health Organization (WHO) today issued a statement warning about a potential health risk due to fine ash particles from the ongoing eruption of Mt. Eyjafjallajokull in Iceland.
People with asthma and other chronic respiratory conditions such as emphysema or bronchitis may be more susceptible to irritation if the ash is in the lower atmosphere or in high concentrations. The ash cloud from the explosion contains very tiny particles of glass, but as long as it remains in the upper atmosphere, it is unlikely to cause untoward health effects, says the WHO.
"Particulate matter is identified according to its diameter," said Maria Neira, MD, Director of Public Health and Environment Department at the WHO, in a statement. "The small particulates less than 10 microns in size are more dangerous because they can penetrate deeper into the lungs."
Experts are analyzing the ash and estimates show that approximately 25% of the particles are less than 10 microns in size, according to the WHO.
"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," Dr. Neira added. "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."
She also advised that people with asthma and other chronic respiratory diseases should avoid strenuous exercise if air pollution increases.
Volcanic eruptions are common in Iceland, but we never hear about them, Pierre Robin, PhD, a geologist from the University of Toronto in Canada, told Medscape Medical News.
"This one has created havoc because of 3 coincidences. Number 1, it erupted under a glacier, and the resulting steam explosion blew the magma, or shards of glass, up to 11 kilometers into the air. Number 2, the jet stream was going by and picked up these tiny particles, and is now carrying them around the world. The jet stream is probably over Moscow already. Number 3, the explosion took place in an area of the world that has the most dense air traffic. If this had occurred in Australia, for example, it would have disrupted air traffic there, but not anywhere else."
The jet stream will continue to carry the tiny shards of glass that make up the volcanic ash for several weeks, Dr. Robin said.
Mt. Eyjafjallajokull remains active, but it is hard to know whether this will continue to have a global effect, he added. "Maybe in 2 days the air traffic interdiction will cease. The eruption might go on for 2 years but the coincidence, or perfect storm of steam explosion and jet stream proximity may never arise again. We just don't know."
Fernando Holguin, MD, MPH, codirector of the University of Pittsburgh Asthma Institute in Pennsylvania, told Medscape Medical News that much of the particulate matter that comes from volcanic eruptions are actually filtered in the upper atmosphere and are not as harmful as the particulate matter that comes from car exhaust, for example, because they are larger.
He believes that any health risks would affect people living relatively close to the eruption and that the risk to people living thousands of miles away is slight.
"Individuals in close proximity to a volcanic eruption get exposed to high concentrations of particles and also large amounts of sulfur dioxide, which is a very powerful airway irritant and can cause transient bronchial constriction, especially if you have asthma and COPD," he said. "But I don't think that would be of much concern to people who are thousands of miles away from the site of a volcanic eruption."
Much more dangerous are the fine particles that are emitted from motor vehicles that are smaller than 2.5 microns. These are harmful to cardiovascular and respiratory health because they are readily deposited in the airways and cross into the blood stream, he said.
