War, Terrorism or Accident it really makes no difference if the air in our environment is contaminated to the point of being toxic. The air we breathe is the most important thing that our bodies must have. In the face of an accidental chemical spill or a terrorist biological or chemical attack we must continue to breathe.
Anyplace - home, office, school - can be sealed from the outside with enough time and money. However the air supply must continue if we are to survive. We could use million dollar air scrubbers with pure oxygen addition and ozone generators for odor control if we had the money.

Most of us can not afford to be fancy, so we use simple steps to clean the air of particles or gases. We find what we need in the closet or attic or at the local hardware store. We invest the time, energy and effort needed to insure the safety of our families. As a song once said, the people in this country will survive.