I bike 20km to work and back a few times a week. Mostly in yarkon park and along beach but with stretches in traffic. I’m mulling a filter to clean my breathing air and possibly air in my goggles, mechanical hepa and carbon cartridges in some kind of cylinder with stacking sections , like. So I was considering also a ‘fluidized bed’ aka sand with water+ bacteria and/or algae. To make that work I blv I’ll need a screen that would allow gas thru but prevent water, does such a thing exist? Maybe the surface tension of water will allow one to avoid a mesh with holes smaller than a water molecule but larger than an oxygen molecule
sounds like reverse osmosis ?
cut it up stack 3 layers on top of each other and that should give you clean air in the street
if you wanna go extra crazier try to get a MERV 17-20
add a small fan and some LI-ION batteries will give you enough clean air for your commutes
below a chart for merv ratings
GE hamster-haters used silicone for underwater chamber of solitude
carbon cloth/paper gas diffusion layers
from wiki on gills: Galen observed that fish had multitudes of openings ( foramina ), big enough to admit gases, but too fine to give passage to water.
This 20 micron sheet may do.
From this datasheet if i have it right the permeability of silicone to air is
Perm = ( vol/time * thickness) / (Area * pressure_diff) = 2700 * 10^-8 cc/s cm / (cm^2 atm)
vol/time = Perm * Area * pressure_diff / thickness = 2.7 * 10^-6 cm^2/( s * atm) * 4^2 cm^2 * 0.1atm / 0.002cm = 0.0021 cc/s
which unfortunately is a few orders of magnitude too low for normal human or , one imagines, gerbil/hamster respiration - so how did the evil GE engineers do it?