How effective is double masking?
The recommendation for double masking is based off the findings of a CDC study. This study looked at ways to improve mask fit to reduce exposure to COVID19.
In the study above, coughing and breathing were simulated using a device that produced aerosol particles that the researchers could quantify after the experiment was completed.
Coughing simulation
In the coughing simulation above, researchers evaluated the effectiveness of:
• A cloth mask alone
• A surgical mask alone
• A cloth mask covering a surgical mask (double mask)
Researchers found that when a cough was simulated, the double mask blocked 85.4 % of the aerosol particles. This is compared to 51.4 & and 56.1 % for the cloth and surgical mask, respectively.
Breathing simulation
The breathing simulation investigated several situations using two models of a human head. One of the models generated aerosol particles (source) while the other was exposed to them (recipient).
Researchers found that
• When the source was wearing a double mask and the recipient was not, the aerosol exposure of the unmasked recipient was reduced by 82.2 %.
• When the recipient was wearing a double mask and the source was not, the aerosol exposure of the double masked recipient was reduced by 83 %.
• When both the source and the recipient wore a double mask, aerosol exposure was reduced by 96.4 %.
Why you should double mask:
In summary, researchers found two important things:
- When compared to either a cloth mask or a surgical mask alone, wearing a double mask was more effective at reducing aerosol exposure from coughing.
- Aerosol exposure through breathing was drastically reduced when both a source and recipient were wearing a double mask.
Double masking and viral variants
In recent months, several variants of the new coronavirus have emerged throughout the world. Some of these variants can spread more easily between individuals.
One variant you may have heard of is B.1.1.7, the “United Kingdom variant.” Public health officials in the United Kingdom have reported that B.1.1.7 is about 50 % more transmissible.
Additionally, according to a 2021 research review, another variant was recently identified in California during a surge in COVID-19 cases. The American Association for the Advancement of Science reports that in research yet to be published, the lab that identified this variant is reporting that, like B.1.1.7, it also appears to be more transmissible.
The rise of more transmissible variants means that taking good preventative measures is even more important than ever. Given its effectiveness, double masking can be an important tool in preventing the spread of these variants.
Comments