[*BCM*] Filter Masks

[Jim Leonard]

On Sun, Jun 10, 2007 at 04:47:43PM -0600, list at moz.geek.nz wrote:
> Ben said:
> > I've used HEPA filter masks and they're no fun to wear.  They get sweaty
> > and you have to exert extra effort to force your incoming air through
> > the filters.
> 
> I use the bike shop filter masks most of the time because I notice a
> difference when I don't - the traffic smells noticably worse and my
> throat is more aggravated after my commute. That may be a purely
> cosmetic difference, but it's enough to make me happy. It also means
> I notice smokers less while I'm riding which is a pleasant benefit.

A mask like this won't filter out any of the toxic gases that motor vehicles
produce but it will take care of the particulates.  Specifically you will
be filtering out the soot from the vehicle exhaust along with pollen and 
road dust.  This is also while you're breathing heavily from exertion so
you'll be pulling more of it into your lungs.

> Of course, while I'm actually wearing the mask all I really notice is
> that my breathing is obstructed.

I wonder how hard it would be to find a positive pressure filtering system.
That could be relatively comfortable to wear but I don't know where I'd 
find such a thing.

--jim