Regarding the by another SurvivalBlog reader that mentioned that she had purchased Nano mask: They have major flaw, so I’d rather choose [a full mask with] 95 filters: The Nano mask offers NO EYE PROTECTION. Think about it, if it can get into your mouth or nose, it’ll get into your eyes too.
Secondly, [swimming] pool grade diatomaceous earth will work too, contrary to what the website says. (I used to own a pool building business for nine years.. – Tamryn
JWR Replies: I agree with both of your points. There are differences between natural diatomaceous earth and the heat-treated (calcined) diatomaceous earth that is used for swimming pool filtration. Swimming pool diatomaceous earth can have a higher crystalline silica content (about 60%) and could be dangerous if taken internally. But it is still fine fro virtually all of the other typical uses–and the markup per pound can be 1000% higher for “store bought” diatomaceous earth. Any other touted difference consists primarily of packaging, marketing, and a bigger mark-up.So I recommend that you buy just a small quantity of “food grade” diatomaceous earth, and a much larger supply of typical swimming pool diatomaceous earth for killing pests and for water filtration. OBTW, diatomaceous earth has 101 uses  around the house: You can uses it to kill insects as a non-toxic alternative to poisons, in water filtration, hydroponics, to dust your chickens for mites, et cetera.
Letter Re: “Nano Masks” (SAs: Asian Avian Flu, Protective Masks)
I saw the post on the blog about the Nano Mask and had to write in to offer some concerns about this system for LONG-TERM usage during an Avian Flu outbreak.
First, as their own web site discloses, if the Nano Mask filtered anything smaller than .027 microns then you would not be able to breath through it as the filter pores would be too small to handle the air flow of our inhalations. So, what they are telling us is that this “nano” filter media ultra-fine filter. Keep that in mind as I discuss the concerns I have…
Nano-Mask concern #1:
The Nano-Mask does not have an EXHALATION VALVE! This means, as their web site confirms, that both air coming IN (inhalation) and air going OUT (exhalation) are both equally filtered through the nano filter media. Unless I have someone in my household that has a weakened immune system, why on earth would I want to FILTER the air coming out of my lungs? Moreover, if properly prepared for a flu pandemic, my home would be a “CLEAN” area where the donning of protective masks would not be needed. Therefore, the only time I will need respiratory protection is when I go out where public contact may or will be expected, so why, again, would I want to filter my exhalations? This makes no sense for “survivalist-type” scenarios…
Nano-Mask concern #2:
MOISTURE!!! Since the nano mask has no exhalation valve and filters both inhalations and exhalations, all that hot, moist air I am exhaling is now DIRECTLY IMPACTING the nano filter media. Add in heavy breathing from physical exertion or stress and you are talking about a huge moisture problem! Unless specifically designed to do so, such as a water filter, moisture DESTROYS a filters ability to operate properly by CLOGGING the filter media with water. Gas mask filters are a great example! There is not a gas mask filter anywhere that I know of that works properly when WET, which is why ALL quality gas masks have EXHALATION VALVES. Think about that!
Nano-Mask concern #3:
SMALL FILTER MEDIA! Take a look at the Nano Mask replaceable filter media; it is a small triangular patch that mounts on a mask assembly. Since the Nano Mask does DOUBLE DUTY by filtering air coming in and air going out, this ultra-fine filter media will CLOG UP at least TWICE AS FAST as a comparable mask with an exhalation valve. Add in the moisture variable from your exhalations upon a small filter media and you have serious EFFECTIVE FILTER LIFESPAN issues!
In conclusion, the Nano filter technology is very promising, but let us keep in mind that the H5N1  virus is not like a “weapons-grade” biological agent as it always needs a CARRIER, such as water droplets (spit, tears, mucous or phlegm) or airborne dust where these water droplets attach themselves. This small virus IS NOT just floating around in the air by itself! Since this small virus, just like the common flu, is always attached to a LARGER PARTICLE, the CDC  and WHO  are justified in promoting N95 filters as effective protection from the H5N1 virus. Lets be real; does anyone really think the CDC and WHO would send in their staff, researchers, nurses and doctors into an H5N1 hot zone without EFFECTIVE protection? THEY are the ones who know the threat, not a company trying to market their masks to a fearful public with misleading information and a questionable product for the intended application.
I think your readers should be aware of the DOWNSIDE to the Nano-Mask as very few think and analyze the LONG-TERM feasibility of a protection product. I personally am recommending to friends and family, similar to the CDC and WHO, any N95 or N100/P100 mask with an EXHALTION VALVE (I like the 3M 9211 N95 mask) combined with lab-quality, shielded eye protection. In a truly contaminated environment (hospital during pandemic), I would not consider myself safe unless I was wearing full-face protection (eyes, nose, mouth) with HEPA  filtration that a good quality military gas mask would provide (I like the Canadian C4 or Scott M95). Then comes DECON . Baruch HaShem Yahweh, – Robert