gas mask as part of prep ??

[BeardyMan]

I have 30 FFP3 masks (disposable) and a Russian gas mask. Looking to buy something for my little boy to wear in the case of pandemic or NCB attack. Yes, it's probably overkill, but I'd rather have it and not need it.
I've only found some escape hoods on American sites so far. All way out of my price range. Does anyone know of anything like a FFP3 mask that could be used by an 18 month old? Something that he can't take off himself would be a bonus, preferable whole head and clear so he doesn't feel like he's in a bag.

If it were a pandemic situation my wife and child would stay at home naturally, but I would need someone to scrub me & the suits down in the clean room before I get into the house proper.