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Comment by fnord77 | Hacker News Reader

these don't have filtered output, do they?

So most of them are vented BUT there are some that are not.

GVS sells one with source control: https://www.gvs.com/en/catalog/elipse-p100-with-source-contr...

Most of 3M's stuff does not have source control but I just discovered tonight that there is an add-on exhaust filter to the 6000 series of masks: https://www.3m.com/3M/en_US/p/d/v101254496/

I wore a 6000 series mask for most of 2020 and 2021 but upgraded to a 7000 series when the elastic wore out on the 6000. Both the 6000s and 7000s are super comfortable. You just might get some strange looks, particularly if you are sporting the bright pink P100 filters. I have not yet been able to find a source control equivalent for the 7000 series.

One great superpower of the 3M masks (6000/7000 etc.) is that wearing one of these while going to a port-a-potty means that you do not smell anything at all =)

Some models (particularly from 3M) can be fit with output filters: https://www.3m.com/3M/en_US/p/d/v101254496/ I have even seen explicit P100 filtering for these output filters.

Anecdotally I just ziptied a surgical mask over the exhaust on mine and it's fine.

There are 3D print attachments you can use. I used them with P100 filters and tested flow. Pretty damned good.

Others will not trust you, however, so I always carry another mask with me to swap to.

No, but if everyone is wearing one it doesn't matter. Some of the masks on this site are vented as well.

Most of the point of wearing a mask is to prevent you from unknowingly spreading COVID to other people. Many stores I visit have signs prohibiting vented masks.

I'm pretty sure a vented mask is at least as effective as a cloth or surgical mask in that regard, both of which mostly contain the aerosol spray rather than actually filter out small particles. I doubt the stores you go to require true respirators?

Apparently the CDC agrees: https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use...

> Yes, an N95 filtering facepiece respirator will protect you and provide source control to protect others. A NIOSH-approved N95 filtering facepiece respirator with an exhalation valve offers the same protection to the wearer as one that does not have a valve. As source control, findings from NIOSH research suggest that, even without covering the valve, N95 respirators with exhalation valves provide the same or better source control than surgical masks, procedure masks, cloth masks, or fabric coverings.

I'm sure its fine for most situations, but you should be aware: below that entry it states that elastomeric respirators (like you are using with P100) are not included in that category:

> Until more is understood on exhalation valves, elastomeric respirators with unfiltered exhalation valves should not be used as source control in surgical and other healthcare settings due to concerns that air coming out of the exhalation valve may contaminate the sterile field.

That's for healthcare and surgery, not for going to the store...

Thus why "I'm sure its fine for most situations". I just want to make sure that when we're throwing around CDC stuff, we're doing it in context.

Goodness knows enough people are taking expert snippets and doing terrible things with them, I'd hate to see HN become a source of that.

If you can't catch it (but the mask does), you can't spread it..

Because of course people wearing vented masks wear them whenever they are near another human. It’s not like they have family or friends they spend time with maskless.

Sad, but true. Those who don't care had to leave..

I've been wearing a surgical mask on top of a valved N99 some of the time. That seems to satisfy. Maybe I could put more serious filtration material over the valve though.

I would like to find some affordable PAPR's (powered air purifying respirators). I see a number of places claiming to make them, but none seem that actually available to buy.

It might be interesting to measure the amount of CO2 inside a mask after a person has been wearing it for a while. There are some differences between mask types, but I don't know if any would appear between mask brands and models. Here is a study where they tested some masks that way:

https://bmcinfectdis.biomedcentral.com/articles/10.1186/s128...

I have a CO2 sensor on order from Adafruit and while try doing some tests like this myself when I can.

I don't see how CO2 or any other exhaled gasses could possibly be an issue if the volume of air inside the mask is significantly smaller than the volume of a breath, which it is by a large factor.

Not anymore with omicron. The rules have changed, your primary focus should be filtering the air you breath. We are two years into this thing and mask compliance for the general public is at the lowest levels possible. You can only protect yourself in public, you have to start wearing masks that protect you primarily.

That's not why nurses and doctors wear elastomeric respirators or PAPR devices.

The effect is multiplicative. If my mask filters 95% of the air on the way out, and yours filters 95% on the way in, that's 99.75% filtration. Add a HEPA into the room, and you're pretty safe.

Studies show the same too.

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