Masks designed to filter smoke will filter smoke, beards will not

Originally published at:

1 Like

What if it’s not your beard, though? Would that work?


When I first read Richard Bachman’s The Running Man, it seemed like a weird dystopian science fiction idea that it would be unsafe to go outside without special protection. It wasn’t long after that I noticed you no longer had to pay extra for UV protection on sunglasses, they all seems to loudly proclaim that feature. And after the last two summers, going outside with extra life support gear seems second nature.

I shudder to think how bad it will have to get before most people decide, “this is messed up, and a policy shift is in order”.


The CA Public health page says:

Some types of masks can also filter out up to 95% of small smoke particles. These masks are marked with one of the following: “P95,” “R95” or “N95”, and tend to be more expensive than ordinary dust masks.

But that’s not what the FDA says:

The ‘N95’ designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small (0.3 micron) test particles. If properly fitted, the filtration capabilities of N95 respirators exceed those of face masks. However, even a properly fitted N95 respirator does not completely eliminate the risk of illness or death.

So it depends on the particles in the smoke. If 10% of the PM in the smoke is PM0.3 or otherwise below 300 nm, then an N95 mask is not going to block 95% of the PM from the smoke. It’s going to block 5% of the 90% that is above 0.3 micron, ideally. I don’t know the size distribution of wildfire PM, so for all I know PM<0.3 is an extremely negligible proportion of the total, in which case the CA Public Health information is correct. It absolutely won’t help in terms of volatile PAH or other hydrocarbon materials from the fire that may also present long term health hazards.


My plan to kill off all hipster males is coming along nicely!


A lot of time in the sun over the years and decades can lead to cataracts, even on a pristine earth, I think. It doesn’t have anything to do with pollution. Of course with the disruption of the ozone layer, it will become worse.


Fine, just jettison the helpless and the razor-impaired. Why did I think Californians were any better?

Add in the fact that 90% of the population would wear an N95 completely wrong won’t help any, either.


It’s Such a Beautiful Day

Isaac Asimov


Wait, does this mean that the beards themselves filter out smoke and particles? How thick does the beard have to be?

My son is using the N95 mask right now outdoors helping a neighbor clear brush. I am waiting to go out and do some simple yard work until he comes back with the mask. We are a bit north of SF and the air is visibly awful, with flecks of ash like something from the upside-down world (I mean TRUMP is president? wtf!)

I am wondering what 90% of us dummies are doing to wear it wrong? Should be quite snug, no drafts or leaks even when you crane your neck around is they way I taught him. Any pro tips? Not being an ass I hope just curious if I’ve been doing it wrong (mb RTFM? =`)




The picture shows proper usage, but in a nutshell, if you feel like you are suffocating, you are using it correctly. I have to use those occasionally at work. They are effective but ungodly uncomfortable.


Got it. I always say if if doesn’t make your face hurt it isn’t tight enough!
Usually makes the bridge of my nose feel like I’ve been in a bar fight.


I bought one of these

but it turns out it has a “HEPA-type permanent filter captures particles as small as 2 microns”. Wildfire smoke particles are smaller - you need to buy “true HEPA”.
Amazon took it back and I got a “true HEPA” machine (after the smoke was mostly gone).

1 Like

Pretty much what docosc said. They are not comfortable, and actually take a little effort to breathe. And if you have any facial hair sticking out, it ain’t working. No beards, smooth shave.

A lot of people will not make it fit correctly, complaining it isn’t comfortable.

1 Like

But hipsters make all the good beer!

1 Like

Well, it wouldn’t surprise me to find out that smoke has particles “as small as” 2 microns, but that wording is interesting. It leaves open the possibilities that A) There are smaller particles and B)That they are of negligible proportions and C) Both or neither. (Unspoken is D)Whether we need to worry about those.)

That said, filter ratings offer narrower information than consumers suspect. This is because it’s actually harder to test for a range of particle sizes and rate by size. It’s easier to rate for a single particle size of greatest concern. Below a few hundred nanometers, different effects dominate the filter dynamics, and then you need to start worrying about things like reaggregation or reaccumulation of particles. What happens with particles below the rating is somewhat unpredictable, and it doesn’t necessarily drop off the way you think it would. Depending on the material the filter might actually start filtering more effectively in certain particle size ranges below the tested range. These are also sensitive to the specific substances involved.

Then there’s the issue of filtering a space. A room with an air filter in it takes considerable time to pump the volume of air through it and to raise the air quality. Opening doors and windows can affect that, as can your home’s HVAC system. What that means is that you’re always breathing lower quality air than the filter is putting out, because your home is not a spaceship. And of course even HEPA filters don’t really do anything about gases and volatile compounds. That’s why you’re often offered a secondary baking soda or carbon filter to remove odors.

None of this is to ridicule anyone’s efforts at limiting their exposure to particulate matter. It’s just to say that when you’re looking at claims on the box, often they mean less than you might think, simply because they can’t promise that much. It doesn’t mean no one should wear a mask, but I, personally (with my specific risk factors and lifestyle) would tend to question whether an N95 mask versus a HEPA mask (also sometimes referred to as N100) for a few weeks really is going to make a massive difference to my health considering that I’m not wearing any mask most of my life. I think more data is needed, especially if annual wildfires are just gonna be a thing now.


We have hardly been outside in days. It is burning eyes and throats weather.


The air around here is a toxic reminder of terrible loss of life and property but at least the sunsets are pretty.