TO GO WITH AFP STORY (FILES) This file photo taken on May 18, 2013 shows a woman blowing her nose in Godewaersvelde, northern France, as the return of pleasant weather marks the arrival of allergenic pollen. One in three persons get affected by an allergy at some point in their lives, but the prevalence of allergies is expected to increase with the evolution of our environment, allergists warn. / AFP PHOTO / PHILIPPE HUGUENPHILIPPE HUGUEN/AFP/Getty Images