Staff Sgt. Kayla Otto, 451st Air Expeditionary Wing bioenvironmental technician, fills the room with smoke to test the effectiveness of the respirators that maintenance and other Airmen wear to protect themselves from hazardous air pollutants here at Kandahar Airfield, Afghanistan, March 26, 2012. The smoke test is used in place of the machines used back in the United States. (U.S. Air Force photo by Staff Sgt. Heather Skinkle)