You see a wide variety of masks and respirators in the grocery store nowadays. Do they protect you?
That depends. Masks have a very different function than respirators.
Masks, like the ones you see doctors wear, are not designed to protect the wearer from airborne microbes. They are intended and designed to prevent the wearer from contaminating the sterile field and to essentially protect the patient from the wearer. Respirators have the opposite function. They are meant to protect the wearer.
They will come with a listed protection factor such as N-95. The N stands for Not resistant to oil. There are also oil Resistant and oil Proof varieties designated with an R or a P. Oil resistance is not a factor at all for most people. We do, however have clients where we have to specify oil proof respirator cartridges. The 95 indicates 95% efficiency at stopping particles .3 microns and greater, assuming the wearer is using the mask properly and the mask has been properly fitted to the face of the wearer. This will work when the virus is attached to droplets or most particles. The SARS-CoV-2 virus by itself is 0.06 to 0.14 μm. This is smaller that any standard air purifying respirator is designed to stop. Theories differ as to whether those small unattached particles are a significant source of airborne transmission.
Wearing a mask or respirator properly can offer protection. Handling it improperly before and after use can actually expose you. Remember that these masks are intended to be single-use disposable items for safety. Reusing a mask or respirator and storing a used one can expose the wearer and others. Touching a used face mask, to remove it can expose the wearer. Imagine this. You wear a respirator for protection and it actually does its job and as a result the outside of the mask is contaminated with the virus. If you touch it with your bare hands to remove it you may have just contaminated your hands. The next thing you touch will also likely be contaminated; your face, your hair as you remove the mask, the inside of the mask or another surface perhaps. Always remove your respirator while wearing a fresh set of gloves and discard your respirator immediately.
The reality is respirators are difficult to come by right now and they are being reused. There is no accepted way to disinfect a single-use respirator. Studies do show that steam and UV light can disinfect such a respirator without affecting its function. If you have a way to do that it will probably be better than reusing it without any treatment. If you don't, maybe hanging it outside in the sunlight for a few hours would be the best alternative. Don't place a used mask in your car or home. I see a lot of contractors riding around with respirators hanging from their rear-view mirrors. Not a good idea if it has been used. Placing a used mask in a bag until the next use is not a good option either.
Wash your hands thoroughly before handling your respirator or mask before putting it on.
When taking off the respirator and when adjusting it while wearing it use a fresh pair of gloves or wash your hands immediately before touching anything else.
This pandemic has caused everyone to be much more thoughtful about almost every aspect of their lives that involve contact with other people and with the items they bring into their homes. Next time you wear your respirator and gloves to the grocery store and wipe down every item as you bring it home, remember to also take care of your respirator properly to stay safe.
Jim Kukalis is an industrial hygienist and certified indoor air quality professional with more than 30 years of experience as a consultant for companies providing air sampling, PPE selection, preparing written programs, performing respirator training and fit testing.