Let’s first consider a simple case: You are wearing your mask daily in a highly polluted area. What happens to your mask after a while, let us say 1-2 months?
First, your mask will get dirty, no doubt. Fine particles stick to your hair, face and clothes as much as they stick to your mask. Here is the definition for fine particles: https://www.greenfacts.org/glossary/def/fine-particles-ultrafine-particles.htm.
And second your filter will not function anymore, as soon as it gets dark grey or black. The chemical reaction of the filter simply will not work anymore.
Now, we need to go a step further and look at one of the key facts. An N95 (or N99) filter is not washable. It will lose the effectiveness if they are washed, even just once. The filter contains activated carbon cotton which is the material that gives it its special feature. And believe me when I say that this is sensitive material. Not in a way that they can’t be folded, but with regard to any liquid getting in touch with them. And water, unfortunately, is one of those liquids which your filter should not get in touch with. If it does get wet for the one or the other reason, make sure that you replace it. That is, if you can! Just be cautious with your N95 filters and read the following: https://medical-dictionary.thefreedictionary.com/N95+respirator.
Having said that, let me ask you a question at this point. What would you rather have: a mask with replaceable filters or a mask without replaceable filters? To not imply anything at this stage, I leave it to you to answer this question. What I like to add here though is the following: the advantages and disadvantages of replaceable filters.
Masks with replaceable filters
First and foremost, you can wash the mask as soon as it gets dirty. The mask can be washed daily if you wish to do so. It will clearly take a bigger toll on the mask if you wash it more regularly than not. But at least it looks clean and is free of particles which you otherwise might breathe in.
Second, you have the possibility to check the filter regularly. You will be able to physically see how much air pollution there is. Even more so, you get a good idea how soon you have to change the filter. Once the surface of the filter is dark grey or black, you should immediately replace it. The filter efficiency is gone. And the dark grey or black matter are the fine particles that you otherwise would breath if you do not wear a mask. It is a real eye opener, I tell you, especially the first time you see it.
Well, to take the worst first: the problem is that replaceable filters generally don’t cover the full area of the mask. But to counter that argument, you need to understand how the particles enter your body. It is needless to say that it is mostly important to cover the area around your mouth and nose. While breathing, this is where and how the particles get to you and into your body. So as long as you keep this portion of your face (and a bit more obviously) covered with a filter, you are well protected.
Now I forgot the other disadvantages…oh, sorry, there are none…
Masks without replaceable filters
The Number 1 and only advantage of masks without replaceable filters is that the filter covers the whole area of the mask. But given that it’s mostly important to cover the area where you breath in, it does not really matter whether it is covering the whole mask or not. As mentioned above, the fine particles only enter your body through your mouse or nose. In that sense, you are well off just getting a mask which has a replaceable filter.
The major problem with non replaceable filters is that you cannot check in what condition your filter is. Given, there are a few masks which provide you with an app where you can check your filter efficiency. But how much does that help, if you have to throw away the whole mask and buy a new one anyway? Besides, these masks are also famous for their luxury status and will cost you the big bucks (30-40 USD per mask). Ask yourself this question: are you willing to spend about 30-40 USD every 1-2 months? Well, I guess not…but I leave the decision to you…
Also, the masks which have an in-built filter are not washable, at least not really. You can take a loosely wet cloth and try to wipe off the surface of the mask. The inside of the mask will be very difficult to wash. And the biggest problem is that the filter cannot be removed before washing and hence making it wet would make your filter ineffective.
I would be very interested in knowing your thoughts about this subject. So please don’t shy away to put your comments below. I will be more than happy to take the discussion further.