Staff Sgt. Allissa Landgraff, a broadcast journalist with the 911th Airlift Wing Public Affairs Office, is measured for an M-50 Joint Service General Purpose Mask at the Pittsburgh International Airport Air Reserve Station, April 29, 2014. A properly fitted gas mask is essential during a possible chemical, biological or radiological threat. (U.S. Air Force photo by Senior Airman Marjorie A. Bowlden)