Despite a blowout in the Gulf of Mexico, the biggest polluter on Earth Day—Apr. 22—was the earth itself, following the earlier eruption of a volcano under Iceland's Eyjafjallajokull glacier with an ash plume up to 11 km high.Prevailing winds carried the ash across Europe forcing unprecedented closings of airspace in several countries for fear of catastrophic damage to aircraft. International economists at Chatham House, home of the Royal Institute of International Affairs in London, said the ash fallout "may have dashed hopes of a recovery" of the European economy this year. Some estimated the loss to the airlines alone at $2 billion while total business losses durin...