Thread by @ghhughes

AusAir say their masks with wool filters are more breathable than the meltblown plastic filters of other masks. Is that true?

To find out I tested 12 different masks for breathability. Aus Air was not the best when compared to meltblown masks. Not even close.

The AusAir AirWeave is a breathable mask but the wool filters are not categorically better than meltblown filters at breathability.

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Understanding the Chart:

You don't want to have to use a lot of suction to draw in air through your mask, so lower pressure drop scores are better and mean the mask is more breathable.

Of the masks I tested, the AusAir AirWeave is somewhat middle of the pack. It is on the more breathable rage of filtering facepiece masks, but not quite under 100 Pa at 85lpm threshold for the most breathable of the three breathability tiers in the new Canadian CA-N95 standard.

Different testing methods may give somewhat different results.

I tested the masks on a silicone mask testing headform. This helps make sure that the filter area that air can go through is similar to when the mask is worn. I connected the headform to a Scince filter testing machine using the 85 liter per minute airflow setting - the airflow rate that NIOSH uses.

It can be surprisingly difficult to get a mask to seal well on a testing headform. I was able to get max N95 mode Fit Test scores of 200+ to confirm excellent face seals on most of the masks.

I could not get the AusAir to seal perfectly on the headform. It doesn't seal well on my face either, but mask fit is very individual. What that means to the breathability test results is that the AusAir may actually have a higher pressure drop and less breathability than shown in the test results since some of the apparent breathability could be from seal leakage.

I threw in a black iMask FFP2 tri-fold into the test because they've always felt kind of hard to breathe through to my subjective sense, but they used to be one of the few "good" black respirator grade masks that could fit test better than, say, loose fitting black KF94s.

The winner by far is the Moldex M4620 N95. This is not surprising because the corrugated filter has more surface area than regular N95s, similar to they way the pleats in a furnace filter give more surface area. This mask has an inner gasket around the full perimeter of the mask for a better seal, but it doesn't have a nose wire, so the mask isn't adjustable other than head strap tension. The corrugations rub my nose in a way that I'd prefer to avoid, but people with smaller noses than mine shouldn't run into that issue.

The Moldex breathability score is so stunning that I'm going to have to re-test to make sure there were no leaks. It should be legit since the mask seal was confirmed with a 200+ N95 mode fit test, though.

There is an old AirQueen Nano in there, too. Aaron Collins used to use one for its consistently mediocre filtration that was a good indicator that his testing set up was giving similar results day to day, along with using a P or N100 (I forget which) as another calibration point. The AirQueen is very thin and light weight, and relatively easy to breathe in, but not as much as I would have expected given its meh filtration.

And then there is the 3M 8511. Those were my pre-pandemic wildfire smoke masks. I never thought of them as being especially breathable, but I guess I was not appreciative of how much better than the average respirator they are in terms of breathability.

Note that this line up of masks, other than the iMask, is a bit skewed. They represent a number of the more breathable masks on the market. Most respirator grade masks aren't under 100Pa.

Is the AusAir a good mask?

Well, it is a lovely mask. The knit over masks are very nice looking. And they do have legit 3d party lab testing showing 99% filtration, and even a couple of fit tests (more about those later). So I think it is a legit mask. And it may be "good enough" for some use cases.

Personally, I'm not able to get good fit test results from the Aus Air. But fit is very individual.

There are some areas where I think AusAir's marketing could use some improvement, and that is when they conflate testing standards.

AusAir masks are tested using the particulate standard for medical face masks, ASTM 2299, not a standard for "respirators," which are masks for respiratory protection. And that may be good enough. But the standards for face masks and respirators are not the same.

The AusAir ASTM 2299 test uses polystyrene particles at 28 liters per minute of air flow. NIOSH uses salt particles at 85 liters per minute, a much tougher test. The ASTM test isn't "bad," but the numbers aren't directly comparable to NIOSH test results.

So, why would AusAir use an obscure to the public ASTM 2299 standard when the public recognizes respirator standards N95, KN95, KF94, FFP2/3 and P2 by name? To my mind it is likely because the AusAir AirWeave can't pass any of the respirator standards.

However, respirator standards may be overkill for filtering bioaerosols. Bioaerosols are less dense than NIOSH salt particles, so perhaps the particulate standard meant for ASTM surgical face masks is more appropriate.

I see respiratory protection as a continuum, with choices ranging from least protection to most protection, and there can be trade offs such as lower breathability as you choose higher levels of protection.

So for some, the AusAir may their sweet spot for respiratory protection. But you can easily get both better filtration and equivalent or better breathability with other masks, such as a 3M Aura or a Wellbefore 3D Pro. Much of that will depend on personal fit, though.

Oh, I almost forgot. Fit testing.

AusAir posted 3 passing fit tests using a rented PortaCount fit testing machine. That's good. Nice transparency and I wish more mask companies would post fit test results. But it doesn't tell you how many people may have been tested who didn't pass a fit test. Maybe everyone tested passed. Maybe the people tested happened to have the perfect face for AusAir, or maybe it was a diverse range of people.

It's hard to extrapolate general fit from a couple of fit tests, which is an issue I run into when reviewing masks - my fit may be very different than your fit.

I was not able to pass a fit test in the AusAir AirWeave, not even when I used N95 mode and a Fix the Mask mask fitter. My best 4 exercise OSHA fit test Fit Factor was 36, not enough to pass the 100 Fit Factor minimum that represents a 1% or less face seal leak. But that doesn't mean they can't fit other people well enough to pass a fit test.

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