Respirators

Image of respirators courtesy of the CDC.

In our COVID Statement, we stated that respirators are necessary to stop the spread of SARS-CoV-2, the virus that causes COVID-19 in people.

SARS-CoV-2 is spread by airborne mechanisms. (Think smoke!) This means that 6 feet of social distance, 15 minute exposure time near someone infectious, etc. are largely meaningless guidelines.

For example: an infectious person could exhale SARS-CoV-2 virions into a small coffee shop for hours and then leave. This person leaves. If you then enter the room without a proper respirator, your chance of infection is substantial because you will breathe what they exhaled (to a degree).

This page has been created due to government agencies failing to provide accurate, helpful guidance for the general public due to conflicts-of-interest. Messaging from agencies have described masks as either optional or a punishment. These are dangerous misgivings.

Keep reading to learn more about how to protect yourself.

Use a button to jump ahead, or just keep reading.

Mask? Respirator?

Types

The Right Problem

Our Goal

You Can Help

Mask? Respirator?

From early 2020, the pandemic response has included the phrase "mask" to mean anything from a piece of fabric with your favorite sports team to a proper respirator, such as an N95 or elastomeric. Even the phrase "mask up" sticks with us.

Let's stop talking about "masks."

Why bother with such a distinction? Respirators are designed and certified (NIOSH in the US, codified under 42 CFR Part 84) to protect the wearer from inhalation hazards; masks (surgical, complying with ASTM F2100-19) are meant to protect others from exhalation hazards like sneezes.

A proper respirator protects YOU; a mask marginally protects people around you.

OSHA only specifies respirators for hazardous environments (medical settings, mines, foundries, etc.). While the CDC recommends respirators on healthcare workers near confirmed COVID patients, masks are relegated to "stopping exhaled droplets" per the CDC (in the context of tuberculosis).

A mask / respirator distinction should be huge: mask is ambiguous; respirator is not.

An airborne virus like SARS-CoV-2 is carried in exhaled aerosols. It moves similar to smoke -- a hitchhiker that travels with gases and other floating particulates. A respirator physically stops the virions from being inhaled.

Droplets Drop, Aerosols Float

Public health agencies are reluctant to admit that SARS-CoV-2 is airborne (an aerosol) because of the ramifications. The cost to mitigate an airborne pathogen indoors would soar into billions of dollars in infrastructure upgrades.

Instead of spending money, blame and burden is shifted onto the individual with droplet dogma. This is why proper OSHA rules are non-existent. This is why the CDC does not describe airborne mitigations.

The harsh reality is that every human exhale contains particulates of varying sizes: some very fine aerosols (singing) and some very large droplets (sneezes). The finer the aerosol, the longer it remains airborne. This is a spectrum of sizes, and "6 feet" (especially in schools, where "3 feet is the new 6 feet") makes absolutely no sense.

Since public health agencies will not demand infrastructure sizes, your best choice is to use equipment that prevents infectious aerosols from being inhaled. Regardless of your vaccination status, a proper respirator physically prevents infection: they are variant agnostic.

Just as people do not drink from the toilet and then load up on antibiotics, it's best to not inhale infectious aerosols and test your immune system. Do not become a breakthrough case.

Types

This is a broad look at the types of respirators available. They are split by the country that certifies them, which is both an important consideration and a hindrance. Legally, in the US, OSHA only specifies NIOSH-approved respirators, such an as N95, N99, etc.

Respirators are designed to fit the shape of faces using measurements known as anthropometry. The fit is important, since unfiltered air will pass through gaps between a face and a respirator.

Some individuals have become pedantic about fit, claiming that a respirator MUST be fitted to your face or it is useless. This is false: as a comparison, surgical masks are massively leaky. An unfitted respirator is guaranteed to be better than a surgical mask.

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Type	Description	Sensor Cost (@ qty 1000)	Range, Accuracy (ppm)
CO2 Equivalent (CO2eq)	This part measures H2 and ethanol (via MEMS) as a CO2 surrogate. Others may rely on different compounds.	$7.10	CO2eq: 400 to 60,000 H2: Max ±40 Ethanol: Max ±50
CO2 NDIR	Measures CO2 IR absorption directly via an emitter / receiver in a chamber.	$41.08	CO2: 400 to 10,000 Accuracy ±(30ppm + 3%)
Photoacoustic CO2	MEMS IR emitter; microphone captures CO2 vibration.	$29.04	CO2: 400 to 5,000 Accuracy ±(40ppm + 3%)

Replace table above with list of respirators and certifying authorities

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KF94, front

The Right Problem

Now that we have the right sensor in the right place, it's important to determine if the right problem is being solved.

For general health considerations, CO2 levels should always remain below 1,000 ppm. (Ideally, below 600 ppm. ASHRAE suggests 700 ppm over outdoors, currently over 400 ppm, which would be 1,100 ppm. )
If a CO2 monitor shows that levels climb beyond this limit, the room may require additional ventilation. Windows may be opened to ensure the room is suitable for the occupancy or current activity. Exercise produces more CO2 per occupant per minute.
An occupied classroom with no mechanical ventilation or windows that open will have CO2 continuously climbing. However, if that same room has multiple HEPA cleaners providing over 6 eACH (equivalent Air Changes per Hour), there is now a disconnect between the level of potentially infectious aerosols and measured CO2: the HEPA removes the aerosols but not the gas.
Indoor CO2 must be measured against outdoor levels. Fresh air contains a little less than 420 ppm CO2 most days in most areas. This changes according to elevation, but respiration rate (ppm per person per hour) is relatively the same.
Trend across time are also important: a room with continuously increasing CO2 is more concerning than a room that stays constant at 600 ppm.

As discussed in the introduction and revisited above, a CO2 monitor in the right place can be used to assess ventilation in a building and correlate a degree of safety for airborne SARS-CoV-2.

Building ventilation and filtration are both NPIs and address one part of safety. PPE, such as properly-fitting respirators (N95 or equivalent, or better) are the other piece. They complement each other. See our COVID Statement for more.

Our Goal

We want to give you a recommendation for a low-cost CO2 monitor that performs as well as the high-end units. If we cannot give you a recommendation, we will design and build an NDIR-based CO2 monitor and sell it at cost. Our price point is around $100 at low volume.

To give you a recommendation, we are currently asking for help from people that have both a low-end and high-end unit to correlate their performance across a wide range of CO2 concentrations, temperatures, relative humidities, and age of products (since sensors drift over time).

NOTICE:
This page was compiled based on current information and may not be construed as medical or legal advice. While the information presented will enable you to better protect yourself, nothing is guaranteed. The content of this page is provided for educational purposes and we cannot be liable for any inaccuracies or misuse of this information.

Page last modified 2022-01-06.