Maddalena Ragona, Department of Statitics, University of Bologna, discusses the economic impact of the volcanic ash crisis on the EU airline industry, by illustrating one possible methods to quantify such impact. 1st HEC workshop on regulation. Emergency regulation under the thread of a catastrophe: a hard look at the volcanic ash crisis. A conference organised by Alberto Alemanno, HEC Paris. 10 & 11 november 2010. More info at http://www.albertoalemanno.eu