I found the info I was looking for regarding nasal spray. This is Jim Humble's answer in one of his interviews. I've included the question.
"Q12 12) When I add the citric acid to the sodium chlorite solution I can soon
Smell the ClO2 in the whole room. Is there any benefit to breathing or
Sniffing this vapor on purpose, for instance so it can reach my sinuses
Or lungs, perhaps? Or is it too harsh on the mucous membranes to breath
"A12 12) Chlorine dioxide does very little damage to membranes, almost none at all. You must be very sensitive as that small amount of Chlorine dioxide generally will not kill many diseases germs. You can, however put it in the type of mist device that sprays a fine cloud and then breath that. It would be good for the sinuses and lungs."