Volcanic ash can be breathed deep into the lungs and cause irritation even in healthy people. But once it falls from a greater distance, like from the cloud currently hovering above Europe, its health effects are often minimal, experts say. The Icelandic volcano that erupted Wednesday has sent an enormous cloud of microscopic basalt ash particles across northern Europe, grounding aircraft across continent. It is drifting above 20,000 feet, high and invisible from the ground.
Europeans should try to stay indoors if ash from Iceland's volcano starts settling, the World Health Organization warned Friday as small amounts of ash fell in Iceland, Scotland and Norway.
