I bought IQAir and tried multiple filters (I think they use potassium permanganate), and I wasn't able to significantly reduce NO2 in my room. 3M masks similarly may work if the toxic gas concentration is far above the high levels, but I couldn't get it from normal/high to low levels.

Maybe you are talking about an integrated air filtration system, as I haven't tried that yet (though I'm planning to try it).