Around the House
How Do I Clean an N95 Mask?
Ideally, the N95 masks should be worn once, then discarded. However, since the COVID-19 pandemic caused a worldwide shortage of N95 masks healthcare professionals, as well as other essential workers, have been looking for ways to safely reuse these masks.
The creator of the N95 mask, Dr. Peter Tsai, came out of retirement at the beginning of the COVID-19 pandemic to help find ways to manufacture N95 masks faster and to figure out how they can be cleaned for reuse. He told the Washington Post that he put in many hours of new research.
“I started working almost 20 hours a day,” said Tsai, “but I didn’t mind.”
You can read the Washington Post article here.
Below are the methods that Dr. Tsai and Dr. Pascal S. C. Juang, recommend for ridding the N95 mask of the coronavirus, which is the cause of COVID-19, as reported in their article published by the Journal of Emergency Medicine on May 1, 2020.
Disclaimer: This article is presented for information purposes only and with the intent to share Dr. Peter Tsai’s and Dr. Pascal S.C. Juang’s suggestions on how to remove the coronavirus from N95 masks, not other contaminants.. Also, researchers at the Association for Professionals in Infection Control and Epidemiology (APIC) and the researchers at N95DECON (a consortium of scientist looking for safe ways to decontaminate N95 masks) agree that decontaminating N95 masks should only be considered when there is a supply shortage, such as during the COVID-19 pandemic. Whenever possible, N95 masks should be used only once, then discarded.
Solution 1: Allow the N95 mask to sit, unused, for at least three days. This is by far the easiest way to rid an N95 mask of the coronavirus, as no special equipment or procedures are needed. If you are capable of hanging your mask on a hook (and not touching it for three days) then you are ready to go!
This simple solution works because the coronavirus has been shown to live for a maximum of three days on N95 masks.
For those that wear an N95 mask daily for work, four (4) masks are required for this solution to be viable. Follow these steps for maximum benefit:
Solution 2: Dry heat the mask in an oven at 158° F for 60 minutes.
Heating the masks to 158° F for one hour does not have a significant effect on the filtering efficiency of the N95 mask (the masks will retain 98.5% of it’s filtering efficiency after dry heating as described.). N95 masks may be heated multiple times, according to research completed by Dr. Tsai and Dr. Juang. However, at the time of this writing, there is no information on how many times is “too many.”
Solution 3: Boil the N95 mask for 5 minutes.
Dr. Tsai and Dr. Juang caution that the boiling method may not be ideal for N95 masks manufactured with paper or tissue materials. Also, the boiling method can distort the shape of the mask, which can affect the seal of the mask. If the mask seal is compromised, then it is not giving the full protection to the user.
BONUS TIP: Drs. Tsai and Juang say that N95 masks should not be cleaned with soap and water or with alcohol.
Soap and water will reduce the filtering efficiency of the mask almost in half, bringing it down to only 54% of its original usefulness. Similarly, alcohol will bring the filtering efficiency down to 67%.
Considering there are three options that keep the usefulness of the N95 mask well above 90%, there is no reason to have to use subpar methods.
The creator of the N95 mask, Dr. Peter Tsai, came out of retirement at the beginning of the COVID-19 pandemic to help find ways to manufacture N95 masks faster and to figure out how they can be cleaned for reuse. He told the Washington Post that he put in many hours of new research.
“I started working almost 20 hours a day,” said Tsai, “but I didn’t mind.”
You can read the Washington Post article here.
Below are the methods that Dr. Tsai and Dr. Pascal S. C. Juang, recommend for ridding the N95 mask of the coronavirus, which is the cause of COVID-19, as reported in their article published by the Journal of Emergency Medicine on May 1, 2020.
Disclaimer: This article is presented for information purposes only and with the intent to share Dr. Peter Tsai’s and Dr. Pascal S.C. Juang’s suggestions on how to remove the coronavirus from N95 masks, not other contaminants.. Also, researchers at the Association for Professionals in Infection Control and Epidemiology (APIC) and the researchers at N95DECON (a consortium of scientist looking for safe ways to decontaminate N95 masks) agree that decontaminating N95 masks should only be considered when there is a supply shortage, such as during the COVID-19 pandemic. Whenever possible, N95 masks should be used only once, then discarded.
Solution 1: Allow the N95 mask to sit, unused, for at least three days. This is by far the easiest way to rid an N95 mask of the coronavirus, as no special equipment or procedures are needed. If you are capable of hanging your mask on a hook (and not touching it for three days) then you are ready to go!
This simple solution works because the coronavirus has been shown to live for a maximum of three days on N95 masks.
For those that wear an N95 mask daily for work, four (4) masks are required for this solution to be viable. Follow these steps for maximum benefit:
- Label your masks with a permanent marker 1 - 4.
- Start by wearing mask “1.”
- At the end of the first day, hang up mask “1” in a safe place (keep in mind, this may be contaminated with coronavirus, so it must be stowed in such a way that an unsuspecting person will not touch it).
- On each subsequent day, where the next mask. Safely stow at the end of each day.
- On the fifth day, wear mask “1” again. Repeat the process as necessary.
- Inspect each mask for damage, or soiling, that may disqualify it as a safe mask to wear.
- There is no change in the filtering efficiency of the N95 mask for this solution.
Solution 2: Dry heat the mask in an oven at 158° F for 60 minutes.
- Place a wooden dowel inside the oven to hang masks.
- Make sure the masks stay at least six inches from the heating elements.
- Inspect straps after heating. Straps may be replaced by stapling new elastic to the mask.
Heating the masks to 158° F for one hour does not have a significant effect on the filtering efficiency of the N95 mask (the masks will retain 98.5% of it’s filtering efficiency after dry heating as described.). N95 masks may be heated multiple times, according to research completed by Dr. Tsai and Dr. Juang. However, at the time of this writing, there is no information on how many times is “too many.”
Solution 3: Boil the N95 mask for 5 minutes.
- The elastic straps should not be submerged in boiling water.
- Do not stir the masks while they are in the boiling water, as this may distort the shape of the mask.
- Allow the mask to air dry. Rushing the drying process can have an adverse effect on the shape of the mask. If the shape of the mask changes, it may not fit properly on the user, thereby lowering the filtering efficiency.
- N95 masks that have been boiled retain 92.4% of their filtering efficiency.
Dr. Tsai and Dr. Juang caution that the boiling method may not be ideal for N95 masks manufactured with paper or tissue materials. Also, the boiling method can distort the shape of the mask, which can affect the seal of the mask. If the mask seal is compromised, then it is not giving the full protection to the user.
BONUS TIP: Drs. Tsai and Juang say that N95 masks should not be cleaned with soap and water or with alcohol.
Soap and water will reduce the filtering efficiency of the mask almost in half, bringing it down to only 54% of its original usefulness. Similarly, alcohol will bring the filtering efficiency down to 67%.
Considering there are three options that keep the usefulness of the N95 mask well above 90%, there is no reason to have to use subpar methods.