The N95 quality face mask is recommended for the swine flu because it filters out very small particles. That is very good for the wearer of this mask when in a public place such as on a public bus, but it doesn’t protect other people if the wearer has the flu and sneezes.
There is a paper thin flap inside the cage which is sprung to the closed position and stays in that closed position when the wearer inhales, which forces all incoming air to be filtered through the fibrous material of the mask. When the wearer breathes out the thin flap is forced into the open position and lets much of the exhaled air pass out through that valve rather than going back out through the fabric material of the mask. This mask is very effective in filtering out foreign material.
I took this mask, glued a filter of fibrous material around the edges over the cage opening, leaving plenty of space below the cage for more easy flow of air out of the mask. Any silicone glue and and fine cloth material might work well for this application but I just happened to have some ShoeGoo brand glue and ShamWow! brand cloth which seem to work well.
I coughed and sneezed as hard as I could for a test and there was no perceptible leakage so I think this would work quite well for a person having a flu and sneezing flu virus. If a family member with the flu wore this improved mask and the other family members even wore the standard mask, there is a good chance they wouldn’t catch the airborne form of the virus. That is the same virus transmitted by hand to the eyes or nose, but if it is airborne it goes deeper into the lungs and throat where it is more dangerous.
(update 2009/05/07) I wore this mask in public, feeling just a bit silly, but discovered there were still some problems. The elastic holding the mask was far too tight and became very uncomfortable and there were no adjustments so I was forced to cut away half of the four elastic bands, down to two, which was much better. The manufacture easily could have made the bands adjustable by making the bands longer and the hold down staples loose enough that they could be pulled through for the adjustment. There isn’t a problem of them pulling out because they are put in reversed and they double back on themsleves. The next problem was that my sunglasses fogged up and later my reading glasses because of the moisture of my breath was rising from the mask instead of blowing away from my nostrils which are pointed away from my glasses, as they are on most other humans I have met. I fixed that problem by putting a small strip of duck tape (some call it duct tape) across the top of the mask.
Another problem was brought on by my own shortsightedness. The filter I put on functioned the same as the mask itself and didn’t let sneezes to pass through the valve. I cured that problem by cutting away the bottom of the newly installed filter which left a large open hole.
That worked just fine and permits the sneeze to blow out okay but isn’t doing as good a job filtering flying viruses. However, because the filter directs the sneeze back toward the throat there isn’t nearly as much risk to nearby people from my flying spit. A better solution would be to find some highly porous cloth and dangle it as a bag from the blow out port. That would look really weird and draw considerable attention at first but it would capture the viruses. Then of course they would be concentrated there and pose a danger so perhaps that bag should have some antiviral agent soaked into it.
None of the flu prevention techniques are likely to be 100% effective but if the transmission rate can be lowered enough the flu will die out before going pandemic and billions of people would be saved from the suffering. The mask I have shown here would lower transmission quite a lot and it is affordable to manufacture and distribute them to everyone on Earth on a short time scale. The flu vacine is has been said will take three years to manufacture enough for all humanity and it won’t be done because it costs too much money. The antiviral drugs like Tamiflu are even more costly and in short supply and will never come close to making it to everyone. The anti-sneeze mask is the best way to stop a pandemic and probably the only way.