Buy it anyway - the fires aren’t going away and the filters are still useful in the absence of smoke.

Masks: https://pksafety.com/3m-7500-series-half-facepiece-respirato...

Filter: https://pksafety.com/3m-2071-p95-particulate-mask-filter-pai...

It’s not my job to help you find N95 masks, they’re available from most hardware stores and definitely from Amazon. I just looked and there’s at least one type available on Amazon that’s not 3M in addition to full respirator masks and everything in between, and it’s easy to find other stores through Google that sell 3M disposable masks if that happens to be the only one you trust.

In addition to that, loose particle filters as spare parts are not uncommon and you can literally strap any filter on a fan, close your windows and start forcing indoor air through it to improve the ambient air quality.

If you have a furnace, you have a filter. Take the filter out of it and stick it on your box fan. Even if it's a little dirty, it's better than nothing.