Mask fit testing just quantifies how well your N95 or other respirator seals on you. That's it. It doesn't turn a switch that makes a mask go from 0 to 100% protection. Particulate respirators that haven't been fit tested will still give you at least some protection or better - the amount of your protection just hasn't been quantified. I mention this because people stuck in areas with wildfire smoke and other particulate pollution are being told by misinformed people that N95s don't do anything without a fit test. That is false. N95s provide protection with or without a fit test. The fit test just tells us how much protection you are getting, and helps you find a model of mask that fits you best for the best protection. But getting fit testing is generally not an available option for the general public, especially during an ongoing disaster, so any N95 or other respirator grade mask is better than none, regardless of whether you have had a fit test. Here's an example: N95s provided 95% filtration **at their worst** - it is the minimum filtration required for certification of an N95 mask. A "poorly fitted" N95 mask might leak 10% ( a 90% seal). 90% of 95% filtration is still 85.5% total filtration efficiency. It's better to have 85.5% filtration than 0%. That is an arbitrary example, and your fit could be anywhere from roughly 50% to 99.9%. Without a fit test you don't know for sure, but it will always be better than nothing. And if you conform the mask's nosewire to your nose bridge well, you'll increase that protection. So, if you are in a situation that you can't leave that has particulate pollution, some protection from an N95 or other respirator grade mask is better than none. It's still best to leave an area with hazardous levels of pollution if possible, or to stay indoors with an air purifier if it is not, and to avoid risk compensation, which is taking on more risk than is warranted by the protection your mask offers. For workplace use, there are benchmarks for how well your mask needs to seal and protect you before you are allowed in hazardous environments. This is a different situation than for the general public already in polluted environments that they aren't able to leave. Keep in mind that I am a fit tester, and a big proponent of fit testing and would like to see it become widely available to everyone, and you should totally go for it if you can get it since it is super helpful. But right now it's not easily available or affordable for the general public, especially not during an ongoing disaster. So don't let perfect be the enemy of good for situations people are already in without a mask and can't leave. Don't keep people from getting some protection just because it isn't perfect protection.