Monday, July 6, 2009

Surgical mask and N95

It seems that there are quite a number of article perpetrating wrong information on the use of surgical mask to prevent from getting flu.

Referring to

It says that surgical mask is for ill people. The mask captures whatever expelled out from the nose and mouth during coughing and sneezing. It does not seal tightly so it only blocks large droplets. However, it is still useful for the ill people to prevent them from infecting others. They are not supposed to wear N95 because they are already with nose problem and wearing N95 may as well kill them due to additional breathing difficulty.

If you want to prevent yourself from catching flu, wear N95. N95 is supposedly fitting tightly to your face. In occupational setting, there is respiratory fit testing you are supposed to take to test how fitting N95 can be on your face. They will get you to breath lots of smell to test. On the other hand, in community testing, at least you have to cup your hand around the seals and inhale or exhale deeply to ensure that no flow is felt around the edge connecting the mask to your face. N95 then will protect you from breathing aerosols containing the virus. The big problem with N95 is that it won't fit in small face (e.g. children) since it's only produced in one size and it won't fit in people with facial hair (no way to create seal around the big mustache and beard.

So if you are the sick one, surgical mask is your choice. Ensure the flexible adjustment around the nose is pressed around your nose and check properly.

If you really feel you need to wear N95 since you are within 2 m of the sick all the time, wear N95 then, don't just wear surgical mask. In your household with flu infected person, just isolate that person and get him to wear mask when he is to common area. Stay away from him 2 m apart. You won't really need N95 or mask then.

Best precaution is still personal hygiene and get away from people displaying flu-like symptom (sneezing, coughing). But remembers, still help them if they need to. Just don't breathe in their direction if possible. The suggested steps if you see people sneezing or coughing near you is to exhale and then move away before inhaling and continuing with normal breathing cycle.

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