Air Filters and Air Cleaners
These are used in several different situations. Whenever the air is dirty and you need to clean that air. Whether it is for a vehicle (they NEED clean air), or for your own lungs, or your children's lungs, these are very helpful in an emergency.
Vehicle Air Filters
When it comes to cars, trucks, RVs, etc, they NEED clean air. Without that, your car sensors and computer could shut down the car if the air was not clean enough. I've read that online. But I doubt it. I would suspect that a check-engine light would come on and the codes would just tell of a air sensor problem. When in reality, the air filter needs to be replaced.
About 10 years ago, I was alerted that under an emergency where lots of debris and ash from a volcano was in the air (like Mount Saint Hellens), that the main problem was that cars wouldn't work, because the air filter was clogged with ash. The car couldn't breath.
Thus, no groceries, no work, no escape for those that had their air filter clogged in their vehicle.
So, I started researching car air filters. What I found was an aftermarket reusable air filter that costs about double a normal disposable air filter, but, one can wash it and keep going. Thus, I recommend buying TWO. One to wash and one to use. Rotate them back and forth to get you down the road.
This is the reusable air filter brand I installed in my vehicles: