150mm pipe kitchen hood exhaust carbon filter cage

My IKEA Underverk kitchen hood doesn't do a very good job of filtering out smells with the stock filters, so I made this cage to put on top of the exhaust pipe. The idea is to have the hood pump the air through an additional layer of activated carbon. I'm honestly not sure how much this actually helps, but I feel like there is a noticeable improvement and maybe someone else wants to give it a try as well ;-)

The width of the carbon layer in my initial prototype (pictured) was 13.5mm, but that seems to be too much. I didn't fill it all the way and there's barely any air moving through the carbon, most is coming out above it. I've adjusted the width to 6mm for a second version, I think this might work better. 

Print upside down without supports. I recommend thick bridges and black filament. PLA works. I used around 1-1.5l of activated carbon for the 13.5mm prototype, the slimmer version will obviously need less. Grain size must be >3mm.

Caveats: Takes a huge amount of time to print. Requires perfectly dry filament, otherwise you'll get a stringy mess. Blows carbon dust around, at least initially. There's no lid and filling is fiddly.

Whatever you do, do not completely block the airflow from the exhaust!