MIRA Safety - VK-530 Filter - Single 40mm Gas Mask Filter - Smoke & Carbon Monoxide Respirator Filters - NATO Standard Size (40mm x 1/7") - Filter Fits Full-Face Respirators - 5 Year Shelf Life

Speaking of the CO thing I believe there are some filters with a layer designed to oxidize it and turn it into CO2 to give you enough time to get to safer air without obliterating all your hemoglobin. Those types of filters are usually intended for emergent structural fires. I can’t remember what they’re called though Edit: found one. Requires a 40mm gas mask tho & it’s not cheap https://a.co/d/0bH47HGj