In my other hub about masks (Dust Mask or Respirator. What's the Difference?) I talked about the use of masks and respirators for home projects such as sanding, grinding, woodworking, remodeling, and gardening. Now let's turn to the use of masks to protect your health. Swine flu (H1N1 virus) is the current concern, but general flu and colds are always a possibility.
We think of a mask as protection against the flu because it covers our nose and mouth – just the places we know where the bad germs will enter our body. So before considering masks, let's take a look at the particles in the air that are out to get us.
Airborne particulates is the term for the contaminants floating in the air. Their size can be measured in microns, short for micrometers. That's one millionth of meter. To give you an idea about size, a human hair is about 100 microns. So we're talking very, very, tiny.
Particulates that are 10 microns or smaller are the ones that are a danger to your respiratory system. An average droplet from a sneeze is over 10 microns. Flu viruses, including the swine flu, is said to be from .08 to .12 microns – that's a lot smaller than 10.
We want to stop those small particulates from entering our body. Masks that cover up the nose and mouth entrance would seem to be a way to do it. So let's look at the surgical and N95 mask.
You've seen them in all the doctor shows – a green surgical mask with the dark eyes of a surgeon worriedly peering over it while desperately attempting to save someone on the operating table.
The doctor, and all healthcare workers (anyone who treats sick people), wear those masks for two reasons:
- Protect themselves from the patient's bodily fluids, such as blood, from entering their nose and mouth.
- Protect the patient from the healthcare worker who might cough or sneeze, thus spreading their own bacteria and viruses.
Surgical masks also help the healthcare worker from touching their nose and mouth, then touching surfaces, such as doorknobs, that other people will then touch. (Thus picking up the evil particulates.)
But the surgical mask does not protect against viruses. After all, these face masks are made of porous cloth or a synthetic fiber and they are loose fitting. This means small airborne particulates can easily get through or around them.
So, if you want to wear a surgical mask outside of a hospital, its primary purpose should be to protect others from your own germs. And if you're sick enough to be wearing a mask, what are you doing out in public anyway?
The N95 Mask
An N95 face mask is actually a type of respirator. A respirator is a mask made to protect your lungs not only against dust and pollen but fumes and other airborne particulates as well.
The N95 mask is a disposable respirator that is intended to filter particles out of the air you breathe. There are nine types of disposable particulate respirators. They are each rated for their filtration ability by the National Institute for Occupational Safety and Health (NIOSH). This is a U.S. agency that conducts scientific research and develops recommendations related to workplace health hazards.
Three of the ratings begin with "N." The "N" stands for not oil resistant. In other words, these should not be worn if the air particulates have oil vapors in them. (We won't discuss the "R" and "P" ratings, which relate to oil-based particulates.) The three "N" ratings, stand for:
- N95 = Filters at least 95% of airborne particles
- N99 = Filters at least 95% of airborne particles
- N100 = Filters at least 99.97% of airborne particles
Many of these masks are rated for airborne particulates of .03 microns or smaller. Doing the math, this means an N95 mask should be able to keep out a flu virus, which is .08 to .12 microns.
- CDC H1N1 Flu | Interim Recommendations for Facemask and Respirator Use to Reduce Novel Influenza A (
CDC recommendations for facemask and respirator
- NIOSH-Approved N95 Disposable Particulate Respirators - 3M to I Suppliers List
Listing of NIOSH-Approved Disposable Particulate Respirators
This is one of the reasons why the Centers for Disease Control and Prevention (CDC) recommends the use of N95 respirators in very limited situations. For example, if you have to care for someone who has the flu.
Additionally, the Institute of Medicine (IOM) has recently advised health care professionals to use N95 masks rather than surgical masks to guard against the swine flu when treating patients. Their tests showed that the protection provided by N95 masks was eight to 12 times greater than that provided by surgical masks.
N95 masks will usually have two elastic straps that fit around your head. Many also come with a flexible aluminum nose strip for a better seal.
There are a number of precautions about using the N95 respirator.
The most important is fit. If the mask doesn't form a tight seal on your face, you're not being protected. Therefore, if you're going to use an N95 face mask, be sure to order the correct size. They come in a range of sizes including large, medium, small, and extra-small. Extra small is intended for a petite woman, not a small child.
If you have face hair (beard, goatee, long sideburns), it is unlikely you will be able to get a good seal from the N95 mask. So if you want to use this type mask, you'll have to go clean-shaven.
The other issue is comfort. If the mask is tight fitting, which it's supposed to be, it can become uncomfortable if worn for long periods of time. The typical amount of time the mask can be worn is from 20 to 45 minutes. After that the mask should be removed and thrown away.
Some N95 masks are sold with some type of exhale valve. This is intended to let the hot air out, making the mask more comfortable, so you can keep in on longer.
Finally, always remember to wash your hands before and after using the N95 respirator.
So, here's the hub in a nutshell. A surgical mask will NOT protect you from the swine flu or any other kind of flu. It's more to protect other people from you. The N95 mask, on the other hand, is rated to keep out small particles. It will offer at least SOME protection from the flu. So if you want to wear a mask, the N95 mask is a better choice than a surgical mask.
The first video shows why surgical masks are not effective for airborne flu.
The second video is from the CDC. It gives you the general instructions for wearing a disposable respirator -- namely, an N95 mask.
Add Your Comment
Jacmo on April 26, 2011:
I was looking for some info for our employees to explain masks and their differences. This was very helpful. Thanks.