Just as small amounts of volcanic ash began to settle in Iceland, Scotland and Norway on Friday, officials from World Health Organization have warned that Europeans should try to stay indoors if ash from Iceland’s volcano starts settling.
WHO spokesman Daniel Epstein said the microscopic ash is potentially dangerous for people when it starts to reach the Earth because inhaled particles can enter the lungs and cause respiratory problems.
“We’re very concerned about it,” Epstein said. “These particles when inhaled can reach the peripheral regions of … the lungs and can cause problems — especially for people with asthma or respiratory problems.” He also said Europeans who go outside might want to consider wearing a mask.
On the other hand, Ken Donaldson, a professor of respiratory toxicology at the University of Edinburgh said, “Not all particles are created equal.” He has studied the impact of volcanic ash in people. “In the great scheme of things, volcanic ash is not all that harmful.”

Find more.