When trying to put the world back together after a SHTF event, staying healthy is of utmost importance! Your cushions, pillows and rugs will at an accelerated rate accumulate dust. This dust build up is impossible to prevent. A large percentage of dust is actually YOU! You shed skin just like a pet dog sheds hair. Dust is impossible to prevent.
This inevitability of dust means that you will need to deal with it on a regular basis. All forms of nasties will feed on this dust accumulation and leave behind their own waste to boot!
Dust in a modern house occurs and in a primitive living home it will accumulate at a much more rapid pace. It isn't very likely you will have a central AC to constantly filter your air. It isn't likely that you will have air purifiers running constantly. And baths will likely decrease even though you will need them more!
So be sure to take the time every month to beat your rugs, pillows and other such items. Always take them outside and give them a good thrashing. As long as you see dust coming off of the item (within reason) continue with the beatings. You want to get rid of as much dust as you can. Drape rugs, etc. over a line and use a stick or better yet make a huge fly swatter just for this purpose.
This simple task will prevent illness. If you find yourself with a scratchy throat when you wake up, then that is a sign that your bedding needs a good thrashing. You've got work to do, so be clean and stay healthy!