If you own your own reg assembly, you could add a 
Bio-Filter Regulator Moisture System to it:
Apollo announces the new bio-filter for all scuba diving 
regulators The Bio-Filter assures clean, moisturized air 
for comfortable and safe diving Scuba divers everywhere 
can enjoy the benefits of this bio-filter by simply 
fitting it to any existing regulator
Many divers are not aware of the difference between 
compressed tank air and air they breathe on the surface 
Compressed tank air is dry (0 1% humidity) and this can 
cause severe discomfort, dry throat, or ’cotton mouth ’ 
More seriously, dry air dries lung tissue and increases 
the risk of decompression sickness Other benefits include 
easier pressure equalization, reduced post-dive headaches, 
increased bottom time, and reduced general fatigue
For scuba diving, it is granted that the supply of ample 
air comes first, but no less crucial is the quality of 
air Moisturized air is essential to pulmonary respiration 
and for comfortable, safer scuba diving The Bio-Filter 
eliminates the problems associated with dry tank air by 
replacing 30-70% humidity back into the tank air the 
diver breathes It also filters out trace particles of 
dust, rust, and odor
The Apollo Bio-Rilter is perfect for all scuba divers 
seeking clean, moisturized air - this includes the adventurous 
travel diver diving in locations where purity with air fills is 
questionable or the weekend diver who seeks comfort and 
additional safety.