[RichH]

"Finished" water, water for food, etc. production stored in vented 'tanks' usually has at least a <3µM filter on the vent - principally to block mold/fungus spores from being aspirated during drawdown of the tank.
Since most 'filters' in this µM size range have poor permeability and poor hydrophobicity .... and 0,2µM hydrophobic PTFE membrane (Goretex !) filters have excellent permeability / air flow, its the 'usual' filter media found there.

BTW - that 'black schitt' typically found growing well down into and inside of your boat water tank vent line is usually fungal. Some of the 'black molds/mildews' are very toxic to human respiratory etc. tissue and damn near impossible to 'cure'. Do websearch: "Stachybotrys Atra"
Botulism (clostridium) is a very rare but still possible airborne 'very very nasty' ... kills lots of ducks and other waterfowl in estuaries/rivers during the height of summer. With some species you only need ONE or two bacteria to pass your lips to kill you. Clostridium toxins are among the 'most fatal' on the planet.

 

[RichH]

pdq - filling of boat tankage usually is not done 'at pressure' but is discharged into atmospheric pressure and with the tank vent outlet 2-3ft. static height above the tank inlet fill pipe. Nevertheless, such hydrophobic membrane systems will typically have a filter pleat 'burst pressure' of 60 psi in the 'forward' direction and 15 psi in the 'reverse' direction.

Youll now find increasingly that most 'commercial transportation' water tankage vent filters (buses, trains, aircraft, etc.) now being applied per CDC, etc. recommendations are of this hydrophobic genre.

BTW - 'dust' in atmospheric air typically runs at 30,000 particles @ ~0,1µM per cubic foot.

;-)