For protection against COVID-19 Coronavirus, people have been using disposable surgical masks or N95 /P2 respirators. With the shortage of these protective masks, people have been advised to sew their own protective cloth masks , which are not as effective but still offer some protection, and are washable.
A further development from these forms of PPE (personal protective equipment) are washable cloth mask which can take disposable filters constructed of the same materials as respirators and surgical masks.
Filter Construction
These disposable masks filters contain a layer of activated charcoal to absorb various gases and vapours such as those from exhaust fumes in traffic when riding a bicycle
The other layers in the filter will trap particles up to 2.5 microns in size, which includes car and diesel exhaust particulates, as well as respiratory droplets in the air which carry COVID-19 coronavirus when people cough or sneeze.
These disposable mask filters have a 5 layer construction, arranged in a specific order, so it matters which way around they’re fitted into a mask!
Which Way Does Replaceable Filter Face in Protective Face Mask?
The front of the disposable filter, which is printed with the words ‘PM2.5’ should be inserted into the mask facing up, towards the inside of the mask, so when you are wearing the mask, it will be on the same side as your face.
How Long Do Disposable Mask Filters Last?
These disposable filters cannot be cleaned or washed, and can be only used be for 1-2 weeks, after which they should be discarded.
The time of 1 to 2 weeks is based on casual use of the mask, such as wearing it only when heading outside the home, going shopping, or riding a bike to and from work, for example. If the mask is worn continuously for a whole 8 hour working day, then the filter will only last 1-2 days!
How Do You Wash the Mask?
- Remove the disposable filter from the cloth mask.
- Gently hand wash the mask in a neutral detergent diluted with water
- Hang the mask to dry in the shade in a location with good air circulation.
Do not leave the mask to soak in the washing liquid or water.
Do not use bleach to clean the mask.
How Well Do These Masks Work?
Studies testing surgical masks have found them around 80% effective at blocking particles in the air such as respiratory droplets that can carry COVID-19 coronavirus when people cough or sneeze, even though surgical masks don’t fit as tightly on the face as N95 / P2 respirators.
These masks fit fairly well, similar to a surgical mask, though the filter material is not as large as that of the surgical mask which are all filter, so they may offer protection close to a surgical mask, but at a much lower cost because only the filter portion is disposable.
It’s important to remember that the point of wearing masks is also to stop the virus being coughed, sneezed or breathed out of your own lungs if you’re infected but asymptomatic (not showing symptoms), as happens in the first two weeks after infection, one of the main ways that community infection spreads.
Wearing a mask that isn’t a respirator still offers a fair degree of protection, it’s way better than nothing, and is also a responsible action to protect the community from yourself in case you’re infected but don’t know it.
With the activated carbon layer in the filter, these masks are a good idea for cyclists who are forced to ride in traffic among all the exhaust fumes.
This type of mask is also commonly worn in Asian countries during the cold winter season to keep the face warm, and to help prevent catching colds or spreading them to others.
For more information on protective face masks, please see the following articles:
Are the carbon filters biodegradable . What council bin do I use to dispose of them?
Hi Susan, great question. The outer layers of the filters are made of a synthetic non-woven polypropylene melt-blown electrostatic polymer which can filter out very fine particles in the air because it has very fine holes in it and also because it acts like an electrostatic dusting cloth, catching small particles and holding them. This special filter fabric is what is also inside the layers of surgical masks and respirators, it’s what makes them work.
Since the filter is made of polypropylene, which is a plastic, it isn’t biodegradable, so you can’t compost the masks. I wouldn’t put them in the recycle bin though with other plastics because they’re constructed from a range of materials, and there’s the risk of disease spreading for the people in recycle centres. I would treat used masks and filters as medical waste, and dispose of it in the regular garbage bin that goes to landfill.
If I dont have a pocket for the filter can I still place it in my mask and not harm my skin?
The filter is made of the same material as surgical masks, so there is no problem with the filter touching your skin. It may be annoying when it moves around when you talk though!
Where can I buy pm2.5 mask filters?
I have bought my mask filters from eBay and from Aliexpress https://www.aliexpress.com/
How often can you wash the filters before they stop working?
When i pull the carbon filter out of my cloth mask (in order to hand wash the cloth mask), How should i store the carbon filter safely until i can put it back into the mask once it has dried?
Hi Adam, the filters are disposable. If you’ve worn the mask long enough so it needs washing, then the filter will be filled with everything that it’s been filtering out of the air, and it’s time to throw it out and put a new one in.