For a smoke/fire situation, I would choose the Safe Escape smoke hood and the Xcaper mask, depending on the storage space situation. Both are reasonably priced and both handle carbon monoxide, so you get the most bang for your buck with them. And the Safe Escape can provide CO protection for up to an hour, which is a huge step up from most smoke hoods that provide 15-20 minutes of CO protection. Hopefully, we are never put into a situation where you can't escape a fire within 20 minutes, but it's nice to know the extra protection is there.

For extended time in a "dusty" situation, those half-face respirators with an appropriate filter cartridge seem to be the best, and aren't too expensive. In a hot environment, or if you're exerting yourself, sweat is going to take a toll on anything made of paper. The face seal is superior on the respirator, although that could become unbearably uncomfortable in hot situations. And if talking to people is important, the respirator can be problematic, too.

Another situation to keep in mind is wildfires, even for urban/suburbanites, like the ones raging in parts of Texas. Toxic gases like carbon monoxide are not such a big concern if you're any distance from the fire, but ash and particulates would be a major lung irritant.

Although I don't get asthma anymore, I have a history of it, so when one wildfire upwind of my neighborhood was pouring smoke on us for a week, I tried wearing an N-95 mask as much as possible, as well as hunkering indoors as much as possible. It's tough wearing that thing all the time. I could not wear one while sleeping because I would often flip onto my stomach and crush the mask.

I assume it helped to wear it, but even with the mask, I started to develop some asthma around day 5 of living with the smoke. Fortunately, that's about when the smoke started to dissipate. I had never really considered wildfires before then. I had the N_95 in my kit primarily for post-quake use, in some dusty environment.

I expanded my supply of N-95 respirators a few years ago once I considered pandemic use, although in reality, considering that pandemics can last years, with waves that last weeks at a time, that's a lot of N-95 masks, and not really practical to buy that many.

Also, N-100/P-100 masks can take a lot of effort to breathe through, if they are worn properly, with a tight seal. Some people, especially older folks with less than ideal lung function, are going to tire of breathing with any extended wear, so something to keep in mind.