Ambient air has an odor after removing respirator

[mp3car]

I have noticed that after wearing a respirator (dual-cartridge activated charcoal by 3M) for an hour or so, when I remove it, the ambient air smells slightly sweet, almost like slight hint of ozone. After a little while without it, the smell seems to "go back to neutral" or nothing unique. I realize there is ozone in the air, but am surprised it'd be enough to smell, and it may not be ozone at all. However, I am assuming it is some kind of an "old-nose" type of thing, the respirator blocks all odors for an extended period, and then I am suddenly exposed to it again... maybe? Anyone have any ideas?

 

[phinds]

Yeah, it's not that the normal air has changed in any way obviously, it's that your nose sensitivity has changed slightly and your experience w/ that might differ from someone else's. That is, what you are experiencing might not be the same thing someone else does.

 

[johnbbahm]

I have noticed that after wearing a respirator (dual-cartridge activated charcoal by 3M) for an hour or so, when I remove it, the ambient air smells slightly sweet, almost like slight hint of ozone. After a little while without it, the smell seems to "go back to neutral" or nothing unique. I realize there is ozone in the air, but am surprised it'd be enough to smell, and it may not be ozone at all. However, I am assuming it is some kind of an "old-nose" type of thing, the respirator blocks all odors for an extended period, and then I am suddenly exposed to it again... maybe? Anyone have any ideas?

I am not a biology person, but looking at this from a Physics point of view, you nose is a collection of sensors.
The respirator filters out things in the air that would normally send signals to your brain, which filters
out a signal from all the noise.
Removing the respirator gives you a burst of what is now a "unique" smell, which after several minuets,
is no longer unique, and so you brain moves it to the noise category.

 

[ensign_nemo]

When I go for a walk in the park, I notice that after walking through a natural area with no cars, I can clearly smell the exhaust from the next car that I encounter with unusual pungency.

It's probably the same effect: after smelling pure air your nose is primed to detect unclean air.