What’s the difference? Let me start with a HEPA filter, because you see these advertised in everything from vacuum cleaners to HVAC air filters for your home. HEPA stands for “High Efficiency Particulate Air.” By definition (there’s a good article on Wikipedia), a HEPA filter will filter out 99.97% of all particulates that are 0.3 microns or larger.

An N95 filter on the other hand, will filter out 95% of all particulates 0.3 microns or larger. Notice that neither the N95 nor the HEPA filter offer 100% protection. In other words, filtering out 95% of particulates means that 5% goes straight on through.

Also keep in mind the efficiency of the filters totally depends on the type of fit you get between the filter and your mouth/nose area. For example, many N95 filters are “one size fits all” and do not fit snugly against the skin allowing air to leak in with every breath. A HEPA filter on the other hand, is usually part of a face mask with soft silicon seals that provide a much better seal against the skin.

Wearing either an N95 or a HEPA filter as part of your job requires that a “fit test” be performed by a trained safety professional in order to verify that you’re getting a good seal. Also, OSHA requires a physical before wearing these types of filters because they do put a load on your respiratory and cardio systems and can possibly trigger problems with those systems (like a heart attack or an asthma attack). My point in mentioning this is that there’s more to it than just buying a filter at Home Depot and slapping it on.

Lastly, a surgical mask will typically filter out anywhere from 80% to 95% of particulates, depending on the type of mask. Surgical mask construction ranges from a simple cloth, gauze-like material to some of the newer, plastic and paper materials that are much more efficient.

However, having said all of that, here’s the kicker. The flu virus is around 0.1 micron in size. Read that again. All of the specs that I listed for filters mentions that they’re effective for particulates down to 0.3 microns. So from a purely scientific stand point, these types of filters are not effective in protecting you from the flu since the virus is too small to be filtered out.

But that’s not the end of the story! There may be some practical benefits to wearing a surgical mask or other type of filter. One is the benefit I mentioned in the article – the fact that in most cases, an infected person is going to sneeze or cough and the virus is going to be expelled into the air along with water and/or mucus droplets. These in all likelihood are large enough to be trapped by a face mask.

A second benefit is that since the mask covers your nose and mouth, it tends to discourage you from touching these areas with your fingers, which may have picked up the virus from a contaminated surface. This might help prevent you from infecting yourself before you can get around to washing your hands.

So basically, the decision whether to wear or not wear a face mask (or an N95 or HEPA filter) ends up being kind of a moot point. You can protect yourself, and your family, much better by taking the simple steps outlined in the article: wash your hands often, keep common surfaces clean, and keep yourself healthy by making sure you eat right, drink plenty of fluids, and get plenty of rest.

As a final note, keep in mind that this virus is NOT a “super” strain of flu. It’s not more powerful than a locomotive, faster than a speeding bullet, or anything else. True, it’s a new strain that hasn’t been seen by the medical community before. But as far as you and I are concerned (the people that are likely to get it), it’s just the plain ‘ol flu.

I’m certainly not trying to trivialize this outbreak, but we shouldn’t go crazy over it either.

Hiram