@edsuom @__philipn__ There are some off the shelf small portable cordless HEPA filters. They're probably useless for filtering a room but probably sufficient to attach a cannula. Probably more expensive and maybe in some way inferior, but definitely easier.
@edsuom @__philipn__ 有一些现成的小型便携式无线 HEPA 过滤器。它们可能无法过滤房间，但可能足以连接插管。可能更贵，可能在某种程度上更差，但绝对更容易。