interesting thread.... but missing a point needing consideration. The 'type' of charcoal you use makes a diff.
Humidity does not clog charcoal. ummm... think fish tank filters, pet drinking fountain filters, your osmosis filter under your kitchen sink....etc etc.
The material the charcoal is made from, the 'mechanical' form factor, and processing itself makes a big difference.
If you really want to understand pulling odors out of the air, go dig around 3D printing forums! we have to pull not only the smell of melting plastics and polymers, but the quite nasty VoCs generated from some of the filament as well.
chars avail - in wood, bamboo, coconut husk...yada yada yada
mech form factors - pellets, re-ground shards, blocks, preforms, etc
processing - acid washed, hot, cold various chemical presses
BIG no-no for fish tanks (people) and especially 3d printers, is acid washed/processed charcoal. Yes,,, the vapors themselves left in the char can RUST BLACK OXIDES SCREWS!! REally! I'm assuming most people might agree you also wouldn't want that recirculating through your air space and into your plants (and YOUR lungs) Scary part, is acid wash is the most common. So just rinse it really well be for use. flush well with water. Re-dry in the oven at about 160-250° tops (min for most home ovens)
Personally, out in my monster 45 gallon air filter/return in my shop dust collector ducting, grow tents, terrariums, 3d printers, all get refilled with generic local fish pet shop aquarium char. heavily washed .
Oh... and even if you don't own a 're-fillable' filter..... just drill out the rivets in one end cap and re-insert a couple short sheet metal screws. Inner filter material?.... hand stretched and scissors trimmed green scotch-bright pads, and or bits of garden bed black cloth make great filter cloth.
Depending on your designs... (like one of my printers) the char fills a womens nylon stock and fills 2 ft of a 4" flexible duct.
ymmv jfft