Fit is the most important thing, and there are piles of civilian models of mask that have great features. your basic canisters are HEPA (N95) small particulate good for most biological and particle stuff (concrete dust sucks) VOC (Volatile organic vapor) most of the gasses would be covered by this, and you can get various others, and combi canisters. However no cartridge will help you with atmospheric problems. ie, Lack of oxygen, CO2, or CO, H2S, high nitrogen levels. Also, depending on whats going on, a full mask may just single you out for greater attention (riot situation) in which case hope you brought a cup, because the gas mask won't help with a ferret round to the nads.