Ash cloud concerns legitimate: report

Concerns for air traffic during volcanic ash cloud were legitimate, according to the Guardian newspaper.
The report in today´s paper (http://www.guardian.co.uk/world/2011/apr/25/air-traffic-volcanic-ash-cloud) says scientific tests found that grains in last April´s ash cloud were sharp enough to put aircraft at risk from abrasion and engine failure
Writing in the journal Proceedings of the National Academy of Sciences, the researchers describe a series of tests on ash collected during the powerful eruptions and afterwards.
The studies revealed the ash cloud to be carrying finer particles, which could be more troublesome to aircraft engines than those released by typical eruptions.