Originally Posted by
Sir Bikesalot
Good info. The Respro does have exhalation valves (so that exhaled breath is not forced back through the filter), but it's true that the filter life is very short (I believe 30 hours of use). Replacements cost about $12, so it's not entirely trivial and on par with respirator cartridges. Really then, it comes down to what level of protection you want and how much bulk you're willing to wear.
Sir Bikesalot,
In that case, the Respro would be on par with the other types of respirators. It was not evident in the advertising I saw that the Respro used exhalation valves to prevent contamination of the charcoal filters. The only reservation I have is that if it only has an exhaust valve, and not an intake valve which separates the inspiration from the filter, then the person's breath could still contaminate the activated charcoal with water vapor. Thanks for the updated information though.
John