Do You Need a Safetulator™ Fresh Air Meter?

Here is the back story about the fresh air meters we sell, which measure CO2 and calculate the amount of fresh air per person in a room. We “make” these meters by taking commercially-available meters and adjusting the setpoints properly so the meters stay in calibration and give the best green-yellow-red indications of the amount of fresh air. (Unfortunately, meters without the proper setpoints quickly become out of calibration and worthless. All this is explained further in my new video: Fresh Air Meters.)

Do you need one of these meters? Yes, if you bring people together inside your building and want to reduce the chance of their spreading covid-19 from one to another. Also, if you want to publicize to people that you are making an effort to reduce the covid-19 risk, including having a good level of fresh air ventilation.

Keep in mind that you may or may not have a well-functioning ventilation system. If not, the needed revisions to the system may be as simple as changing a setpoint, or as complicated and expensive as a whole new system.

You may be asking, how effective is extra fresh air ventilation, and how much should we have? We don’t really know. However, the World Health Organization does have a fresh air standard, and the CDC has a “potential target benchmark for good ventilation” and these are what we use to set the green-yellow-red indication on our meters.

What we DO know, is that no single measure, extra fresh air, masks, etc. will guarantee complete safety. Here is a sad case history. The owner of one of our meters is in a business where clients come in to the building for various amounts of time, in meetings with employees. In this case, a single client spent six hours in a room with an employee. Both people were masked, they mostly kept six feet apart, and a Safetulator™ meter was in constant use, with windows opened as needed to “keep it in the green”. They completed the six hours of work. Early the next morning, the client woke up with covid-19 symptoms, and then got tested for covid-19 with the result being positive. Of course everyone was worried—after five days, the employee was still OK, but ultimately did get the disease. (They both have now recovered.)

Not all possible safety measures were taken in this case. Additionally, they could have:

  • done a PCR test 24 to 48 hours before the start of their day together, allowing enough time to get the results back,

  • carefully inquired for any possible symptoms before starting the meeting (upcoming blog post),

  • worn N95 masks (see Jan. 4th blog post),

  • run an air purifier to filter out virus at a rate of 100 cfm/person or higher—this would be in addition to the 30 cfm/person of fresh air being provided by “being in the green” (see Jan. 11th blog post).

Remember, as my nurse friend stresses, exposure to the virus is cumulative. The virus can be transmitted (without masks) in as little as five minutes, and exposures to the virus can build up over time. Each person’s immune system has a certain capacity to successfully fight off the disease, and when this limit is reached, the additional exposure can let the virus establish itself in your body.

So while fresh air is just one of several important measures, if you are willing to make good fresh air a priority—to reduce covid-19 risk and also for general health—then you need a Safetulator™ fresh air meter. My nurse friend adds that the benefits of good fresh air would equally apply to any upper respiratory disease (flu, common cold, pneumonia). Flu numbers were down last year because people were masked and physically distancing when symptoms were evident. An additional question to ask would be “Were you exposed to anyone with cold-like symptoms in the last 72 hours?” It is often an eye-opener when the exposure question is asked in that manner.

A complete guide on how to use the meter is mentioned in our Dec. 9th blog post, in the document Improving COVID-19 Safety within Buildings - A Do-It-Yourself Guide for Building Operators (PDF).

We don't have live comments or feedback set up yet for blog posts, but you're always welcome to email us at safetulator@kohlerandlewis.com and tell us if you'd like us to post your comment.

Good News / Bad News / Future News

==> Good News: Research is agreeing with anecdotal evidence that Omicron symptoms are much milder than those of Delta.

"Risks in the ... Omicron cohort ... were consistently less than half those in the Delta cohort: Emergency Department visit--4.55% vs. 15.22% ...; hospitalization--1.75% vs. 3.95% ...; ICU admission--0.26% vs. 0.78% ...; mechanical ventilation: 0.07% vs. 0.43% .... "

medRxiv.org - January 2, 2022

==> Bad News: But Omicron isn't mild for hospitals - or people who depend on them.

“Already, this surge is pushing their hospitals to the edge. And this is just the beginning.”

“By the end of the month, according to the CDC’s forecasts, COVID will be sending at least 24,700 and up to 53,700 Americans to the hospital every single day.”

“Omicron’s main threat is its extreme contagiousness. It is infecting so many people that even if a smaller proportion need hospital care, the absolute numbers are still enough to saturate the system.”

“To be clear, these problems are not affecting just COVID patients, but all patients.”

“I don’t think people will realize what’s happening until we fall off that cliff—until you call 911 and no one comes, or you need that emergency surgery and we can’t do it,” Swaminathan said.”

The Atlantic - January 7, 2022

==> Future News: Anticipating the future of Omicron and what might come next.

"Omicron triumphed over delta — another fast-spreading and most prevalent variant — because it spreads so quickly. While delta settles in the lungs, omicron favors the upper airways, where it can spew out copies of itself while we talk and breathe. Its incubation period is only three days, compared to 4.3 days for delta and five days for other variants. It also is more likely than other variants to be asymptomatic; rather than lying in bed, infected people tend to feel fine or only slightly ill, and spread it.”

"In the U.S., experts predict that we’ll see a precipitous decline in omicron cases starting the third or fourth week in January, if we follow trends seen in South Africa, Denmark and the United Kingdom. By mid-February, omicron will recede. But that isn’t necessarily cause to celebrate."

The Mercury News - January 11, 2022

Air Purifiers On Sale

No, not from us. But our favorite models are being discontinued, so now is the time to buy.

The story: In the first year of the pandemic, several schools we worked with were not going to be able to make the extensive and expensive fresh air ventilation improvements to provide 100% of the needed fresh air. So we did the best we could with existing equipment, made minor modifications, and supplemented this with in-room air purifiers. As you may know, virus in the air can be removed by flushing it out with fresh air, or filtering it out with a HEPA filter—and, most importantly, these can be both happening at the same time. Open your windows AND run your air purifiers. (This is backwards from what we used to do when thinking that the polluted air was outside—now the “polluted” air is inside, so things are reversed.)

We explained air purifiers in our Sept. 30, 2020 report. You can see the whole report at COVID-19 Mechanical Engineering Recommendations (PDF). The last three pages of this report are the HEPA Air Filtration Unit Selection Guide, reprinted below.

Blueair is discontinuing the Classic 205 and Classic 605. They may still be available on the Blueair website, and they are also available from Amazon and other sources, at big discount prices. The 205 is my favorite model—we have dozens of them in schools—and is easy to carry around if you sometimes need it portable. Search for "Blueair Classic 205 Air Purifier”, with the quotes.

Sizing note: You should have a minimum of 15 cfm/person of real fresh air. Beyond that, you can provide additional fresh air and/or purified air. For purified air, I recommend an additional 10 cfm/person as a minimum. (See Improving COVID-19 Safety within Buildings - A Do-It-Yourself Guide for Building Operators (PDF) for more information.) Good luck, and here’s to breathing cleaner air!

HEPA Air Filtration Unit Selection Guide:

The COVID-19 pandemic has made air filtration units very popular, with some models hard to get. And it has led to a confusing cacophony of products and claims. Here is a simple guide to sensible selection of filtration units. While the guide is simple, the selection of the units is not simple, due to many misleading claims and unnecessary bells and whistles.

We suggest four criteria:

  1. Be big enough – 100 cfm minimum.

  2. Have true HEPA filtration.

  3. Be quiet enough for a classroom.

  4. Be a mechanical filter only – no snake oil.

1. Be Big Enough – 100 cfm Minimum

Manufacturers misleadingly claim large airflow rates that are possible only with noise levels comparable to those of a window air conditioner. And the actual airflow rates at lower fan speeds are usually not listed and not available. A rule of thumb is to assume that the actual usable airflow rate is a third to a half of the advertised rate.

Unless you are getting a unit for a small office, a flow rate of 100 cfm is a good minimum. If first cost is paramount, then you may find that multiple 100-cfm units will have the lowest cost.

2. Have True HEPA Filtration

HEPA (High Efficiency Particulate Air) filtration removes at least 99.9% of airborne particles of a wide range of sizes (0.01 – 10 microns, a range that includes the size of COVID-19 viruses). Lesser filtration efficiency also would be acceptable, but HEPA filtration is such a popular standard that more filtration units are available with it than without it.

3. Be Quiet Enough for a Classroom

We suggest a maximum noise level of 45 dBA. For most brands, compliance with this criterion is difficult to pin down prior to purchasing a filtration unit, due to the lack of published data. (However, see our Recommended Selections, below.) An ideal classroom will have even lower noise levels of 40 dBA or less, but this level is not achievable with HEPA filtration units except at very high cost per cfm, and background noise levels may be this high anyway.

4. Be A Mechanical Filter Only – No Snake Oil

With a 99.9% efficient filter, why would you need anything more? Answer: you don’t. You don’t need an air ionizer – or if your selected unit comes with one, just turn it off. Be aware that some units do not let you turn it off, so avoid these units. You don’t need Microban, silver nano-particles, or any other anti-bacterial treatment of the filters or any part of the unit. (The federal government rightly is discouraging the use of this class of products.) They have no effect on viruses in any case. You don’t need ultraviolet light, or photo electrochemical oxidation, or plasmawave technology, etc. You don’t need an “air quality sensor” measuring particles or Volatile Organic Compounds.

A carbon prefilter is fine – this removes gaseous organic chemicals, including odors.

Recommended Selections

Here are recommended selections that meet all four criteria. All of them have been widely available lately, and current shipping estimates are shown below.

• Honeywell HPA300, 100 cfm (our measurement) at 45 dBA (our measurement at 3 feet) on “Germ” (lowest speed), about $300, Energy Star Rated. (Ships in 7 days at Amazon)

• Blueair Classic 205, 140 cfm at 44 dBA on medium speed, about $400, Energy Star Rated. (Ships in 7 days at Amazon)

• Blueair Classic 605, 275 cfm at 44 dBA on medium speed, about $850, Energy Star Rated. (Ships in 5 days at Amazon)

Choice of Fan Speed

Use the selected quiet speed during normal operation. During mealtimes, when most masks are off, and the room is already noisy, run the unit at maximum speed = maximum airflow. (Notes on masks: N95 masks offer much better protection than cloth or fabric face coverings, and we have heard from teachers who keep their masks on while the students are eating.)

Our Revised Company Policy on Covid-19 Safety

Yes, everything keeps changing as Omicron takes over. Now typically three days for transmission, not five. Now the antigen tests we have come to rely on aren’t always fast enough to detect early disease. And, the CDC’s community transmission map is 99% red.

And so, we are revising our company policy on covid-19 safety, shown below.

In the office:

  • fresh air levels above 30 cfm/person (CO2 below 750 ppm)

  • HEPA air filtration above 60 cfm/person

  • humidification in winter—a new posting coming soon on this

  • masks for multiple people in the same room

Out of the office:

  • we all share the same approach of being active to avoid exposure

  • avoid going into buildings when possible (curbside pickup, etc.)

  • masks when in a building with people outside our family bubbles

  • we often check CO2 levels when going into buildings, and leave quickly if they are “in the red"

COVID-19 testing (without symptoms):

  • PCR testing 2-3 days prior to, and 4-5 days after any contact with outside people that might pose added risk

  • the company provides BinaxNOW antigen tests as needed by employees, but we now reserve these mostly for testing post-covid

Close contact exposure to covid-19 positive person (we have no symptoms):

  • isolate immediately

  • be sensitive to development of any symptoms (see current symptoms list below)

  • get a PCR test 48-72 hours post exposure or as soon as possible after that timeframe (unless you have symptoms, then test immediately)

  • if there are still no symptoms, return to work after five days of isolation, plus the negative PCR result

  • (contact day is Day 0, then Days 1-5 are isolation, then day 6 is return)

If we have any symptoms (for current symptoms list, see below):

  • we stay home, often doing work from home

  • get a PCR test for as soon as possible - or an antigen test after 24, 48, and 72 hours

  • consider isolating from family members until you get the PCR test results

Return to in-person work after having covid-19 or with positive PCR test when we have:

  • two negative antigen tests (24 hours apart) or one negative PCR test, AND

  • ten days after first symptoms (or positive PCR test), AND

  • 24 hours after last transmissible symptoms (my nurse friend says: "I recommend staying home until 24 hours symptom-free, as there are severe strains of flu out there this season, in addition to covid-19”)

  • Transmissible = Fever, cough, sinus congestion, sore throat, chest congestion, shortness of breath, diarrhea, nausea or vomiting. (Loss of taste/smell, fatigue, brain fog or loss of appetite do not qualify as transmissible.) Headache may be a sign of impending or lingering transmissible symptoms, and should be regarded as such until 48 hours has passed without the headache. If there is not yet a negative test result, a lingering cough should be regarded as transmissible within 21 days of first symptoms. With negative test results, and ten days, and no other symptoms, then a lingering cough can be regarded as not transmissible.

“The latest COVID-19 testing worry? A rapid test that can’t detect omicron in the early days of an infection”

Two articles came out yesterday that, if true, show that the false negatives and false positives numbers from 2020 that I have been using are now out of date. My old numbers were posted Dec. 9th in the “Appendices” and showed low false negatives and false positives for the BinaxNOW tests.

But now with at least 15% false negatives, it doesn’t seem like we can rely on these for early detection, except maybe if you do two tests 24 hours apart? Some people say the antigen tests are good for knowing when you’re not contagious any more, which is something that PCR tests cannot do reliably (many false positives).

Soon, I’ll have an update to our company policy. Here are the two articles:

StatNews 1/6/2022: Make Home Covid 19 Tests Highly Sensitive to Infection

We don't have live comments or feedback set up yet for blog posts, but you're always welcome to email us at safetulator@kohlerandlewis.com and tell us if you'd like us to post your comment.

Masks Unmasked

I’ve made a few short videos to explain how I personally handle masks. My philosophy is that if you’re going to wear a mask, why not wear one that does the best job it can? Loose masks, such as surgical masks with their gaps on the sides, worn and handled carelessly, do almost no good at all. On the other hand, I think that a good mask, well fitted, can reduce your risk by a large percentage, something on the order of the benefit you get from good fresh air ventilation.

The first video is an introduction to masks and mask-wearing. I mention “N95” and “KN95” masks in the video. Our current favorite N95 mask is "Kimberly-Clark PROFESSIONAL N95 Pouch Respirator (53358), NIOSH-Approved, Made in U.S.A., Regular Size, 50 Respirators/Bag, White” which is widely available. KN95 masks are even more widely available and we don’t have a particular brand recommendation.

Masks

The second video is one I made a few months ago, when I first got a new type of mask that FINALLY eliminates the problem of re-breathing your air, and does it in a very clever way. I made the video completely tongue-in-cheek as if my company had developed and was selling the mask. WE ARE NOT. But it explains the device well. The company that makes it, in China, apparently makes a wide range of air purification products including big equipment installed in buildings, much like the equipment that we specify and use in buildings here in New England. So I’m guessing that it really is a HEPA filter in this product and that it really works. This mask is available on Amazon and other places—search for "BROAD AirPro Mask Rechargeable Reusable Air Purifying Respirator with a HEPA Filter."

Safetulator Fresh Air Mask

I tested the BROAD AirPro Mask for several months, found that it can be worn comfortably for many hours, and that I like it better if I use a different (N95) mask than the KN95 masks supplied with the package. It’s easy to modify any mask of your choice to work, and I made a video showing how to do that.

Modifying Mask

Finally, you're not getting the most out of any mask if you just stuff it in your pocket when you’re done, and then pull it out to reuse the next day or at the next store. This video shows how I have been handling masks for the last year and a half. These techniques may seem bothersome to you at first, but for me it’s now a familiar habit that seems no trouble at all.

Sterilizing Masks

I join you in hoping that 2022 brings us the end of everyday mask wearing! But in the meantime, here is what I have developed to make the best of it.

We don't have live comments or feedback set up yet for blog posts, but you're always welcome to email us at safetulator@kohlerandlewis.com and tell us if you'd like us to post your comment.