Yes, it’s a good idea to double mask!
How well a mask can protect you from getting and spreading COVID-19 depends on several factors, including:
- How well a mask fits,
- How well the mask filters the air, and
- How many layers the mask has.
The CDC recommends increasing mask protection by improving the fit and filtration. Improving the mask fit helps prevent air that may contain respiratory particles (with the virus) from flowing around the edges of the mask. Instead, air is forced to flow through the mask. Improving mask filtration causes more respiratory particles to be captured by the mask as they pass through. In both cases, better masks work by reducing the number of respiratory particles that can be inhaled or exhaled by you or people nearby.
How to improve mask fit and filtration?
To improve mask fit over the mouth and nose, there are several options to prevent gaps on the top and side edges of the mask. Look for masks that have an embedded metal nose wire. Or try using devices called mask fitters or braces that fit over a cloth or surgical mask. If you have a surgical mask that is too loose, you can knot and tuck the ear loops. (Here’s a short video about how to do this).
The best way to improve mask filtration is by adding more layers of material between your mouth and the air. Surgical masks, multi-layer cloth masks, and masks with an air filtration pocket are good options. Wearing two masks, called “double masking,” is more effective.
In fact, a recent laboratory-based study by the CDC found that either knotting and tucking a surgical mask, or wearing a surgical mask under a cloth mask, provided better protection to the wearer and to others, compared to a cloth mask by itself or a surgical mask by itself (respiratory particles were reduced by >95%).
When double-masking, make sure that breathing is not difficult and that the extra layer of mask does not block your vision. Refer to the CDC guidance on when to wear a mask and selecting the right mask for the right situation. And remember choosing and wearing a mask is just one of many strategies to reduce the spread of COVID-19.
Last update: 02 24, 2021, 12:14pm ET
Science review: SGB, ERS