Many potential terrorist attacks could send tiny microscopic "junk" into the air. For example, an explosion may release very fine debris that can cause lung damage. A biological attack may release germs that can make you sick if inhaled or absorbed through open cuts. Many of these agents can only hurt you if they get into your body, so think about creating a barrier between yourself and any contamination.
Nose and Mouth Protection
Face masks or dense-weave cotton material, that snugly covers your nose and mouth and is specifically fit for each member of the family. Do whatever you can to make the best fit possible for children.
Be prepared to improvise with what you have on hand to protect your nose, mouth, eyes and cuts in your skin. Anything that fits snugly over your nose and mouth. It is very important that most of the air you breathe comes through the mask or cloth, not around it. There are also a variety of face masks readily available in hardware stores that are rated based on how small a particle they can filter in an industrial setting.
Given the different types of attacks that could occur, there is not one solution for masking. For instance, simple cloth face masks can filter some of the airborne "junk" or germs you might breathe into your body, but will probably not protect you from chemical gases. Still, something over your nose and mouth in an emergency is better than nothing. Limiting how much "junk" gets into your body may impact whether or not you get sick or develop disease.
There are circumstances when staying put and creating a barrier between yourself and potentially contaminated air outside, a process known as "shelter-in-place" is a matter of survival. You can use these things to tape up windows, doors and air vents if you need to seal off a room from outside contamination. Consider precutting and labeling these materials. Anything you can do in advance will save time when it counts.
Use available information to assess the situation. If you see large amounts of debris in the air, or if local authorities say the air is badly contaminated, you can use these things to tape up windows, doors and air vents if you need to seal off a room. Read more: Deciding to Stay or Go.
HEPA (High Efficiency Particulate Air Filtration) Filter Fans
Once you have sealed a room with plastic sheeting and duct tape you may have created a better barrier between you and any contaminants that may be outside. However, no seal is perfect and some leakage is likely. In addition to which, you may find yourself in a space that is already contaminated to some degree.
Consider a portable air purifier, with a HEPA filter, to help remove contaminants from the room where you are sheltering. These highly efficient filters have small sieves that can capture very tiny particles, including some biological agents. Once trapped within a HEPA filter contaminants cannot get into your body and make you sick. While these filters are excellent at filtering dander, dust, molds, smoke, biological agents and other contaminants, they will not stop chemical gases.
Some people, particularly those with severe allergies and asthma, use HEPA filters in masks, portable air purifiers as well as in larger home or industrial models to continuously filter the air.