Originally Posted by
Sir Bikesalot
John, I think the point with masks like the Respro is to provide reasonable mitigation of particulates/VOCs along with higher airflow and less restricted breathing than you would typically get from the usual half-face respirators. I don't think anyone is claiming they are as effective as NIOSH/OSHA certified equipment, but then again those wouldn't be practical for the majority of bike commuters anyway. Afterall, the best protection is the one you'll actually wear. Ergonomics is a key.
Ultimately, a light-duty mask like the Respro, combined with your advice about reducing exposure (distance, shielding, etc.) is something everyone can easily get into and should go a long way towards minimizing the risk to an acceptable level.
I agree with that statement, except for the part about the half-face mask being hard to breath through. With only the two HEPA filters in the mask, there is a very large surface area that you breath through (the filter is folded inside the cartridge), so the inhalation resistance is less. It is not going through an activated charcoal cartridge (which is an option), but only filtering out the particles. I have never seen figures on how much (in inches of water) effort it takes for these masks, but that would not be too hard to determine (at tha sacrifice of a mask, however). So I'll stick with the NIOSH certified equipment (OSHA doesn't certify anything).
John