Let’s Clear the Air PD Session

 Question: How can a teacher check if the ventilation is on in their classroom? Should they feel air movement at both the supply and return vents?

Answer John Oudyk: Using a tissue, ribbon, soap bubbles, smoke tube, whatever will visibly move when the air passes over it, will tell you if there is air movement.  Some thermostats (if they give you control over the settings) have a switch for the fan controls – switching the fan switch to “ON” allows the fan to run all the time (which is a good thing because it keeps bringing in a certain proportion of outside air), whereas if the switch is in the “AUTO” position the fan (and the outdoor air it delivers to the room) only operates when the thermostat calls for heat or cooling.  However, if the temperature is within the target range set by the thermostat, the fan will not operate when set on “AUTO”, so no outdoor air with the recirculated air will be delivered.  So, making sure the thermostat fan setting is on “ON” is something a teacher can check.  Now all this only tells you if the ventilation is on, it doesn’t tell you whether the ventilation is sufficient (more on that below). 

Question: How many ACH should my classroom get to mitigate the spread of viruses?

Answer John Oudyk: This is a tough question because there are many different viruses.  The protective measures that were used during the pandemic worked for some viruses (COVID and influenza) but not others (rhinoviruses (i.e., the common cold)) and it probably depends on how well the virus survives outside the host (i.e., the infected person).  COVID and influenza seem more susceptible to ventilation controls than some other viruses.  The targets for ventilation during the pandemic ranged from at least 6-10 outdoor air changes (or filtered equivalents) per hour or more.  Initially it was suggested that none of the air be recirculated if SARS-CoV-2 virus was present, however, that quickly changed and ultimately it seemed to settle on at least complying with ASHRAE 62.1 which suggests a minimum of about 2-3 ACH (outdoor air or filtered equivalent).  We put together a workshop with a spreadsheet to help teachers measure the equivalent outdoor air/filtered ACH in their rooms – the video can be watched at https://www.youtube.com/watch?v=cYb8rAR7ZMk&t=1s, and the spreadsheet is available at https://www.ohcow.on.ca/covid-19/ventilation-calculation-tool/.

Question: How much does a CO2 monitor cost? 

Answer Joe Vipond: The cost of an Aranet4 is $400 to $500. If you can't afford one a group of people could pool money together and share one.

Answer Let's Clear the Air Representative: In Alberta Red Deer Public Library, Edmonton Public Library, and High River Public Library have CO2 monitor lending programs.

Answer John Oudyk: Great answers – the Aranet4 (the one shown in the presentation) is about $400-500. You should get a monitor that is capable of data logging (i.e., it stores the data and allows you to download it). 

Question: How can a teacher use a CO2 monitor to calculate ACH?

Answer John Oudyk: There is a simple formula that you can apply to the CO2 decay curve which I showed in my presentation (nice exercise for a Math class).  Our spreadsheet which I mentioned in the presentation too, also allows such a calculation.  There are many calculators but not all will convert CO2 concentrations to ACH.  This method works best for a naturally ventilated (i.e., no forced air ventilation) room.  The problem with using this decay curve calculation in a room that is ventilated by a ventilation system connected to other rooms is that the background CO2 level is affected by the CO2 in the other rooms and so it may not work so well.  Also if you are using MERV 13 (or better) filters, the equivalent to outdoor air exchanges will not be measured by the CO2 concentrations.  The rule of thumb of keeping the CO2 levels below 800-900 ppm might be sufficient without getting into calculating ACH.  Compliance with ASHRAE 62.1 (which measures air quality by the number of CFM of outdoor air supplied for each occupant and square foot area of the room) implies CO2 levels around 1000-1200 ppm. 

Question: How many days of CO2 readings should a teacher use to determine if the ventilation in their school is adequate?

Answer John Oudyk: This is a sampling strategy question. Ventilation is supposed to be designed to adequately ventilate the space at peak occupancy, so if you measure during the “worst-case scenario” then you don’t need to measure at conditions less than this.  The more data, generally, the better.  I personally like to analyze the time curve of the growth and decay of the CO2 concentration because this tells me a lot about the operation of the ventilation system and how much outdoor air it is bringing in.  The peak CO2 concentration is the data point you should compare to the your criteria (NOT the 24-hr time weighted average nor the 8-hr average). 

Question: If the CO2 readings are getting high what can a teacher do to decrease the CO2 right then?

Answer Let's Clear the Air Representative:  A teacher can open windows in their classroom if possible, open doors, or take their class outside for a while.

Answer John Oudyk: Again, all good answers.  Allowing a cross draft through the room (open door and open windows) is probably the quickest way.  Putting a box fan in the window blowing in the outdoor direction with other windows open to allow the outdoor air to come in also works well (I use this technique in my house at home when it gets hot and stuffy).  You might need to experiment a bit with opening and closing different windows and doors until you find the best air flow pattern (it may differ under differing wind conditions).  Reducing occupancy (going outside for recess/lunch/gym) obviously will help and opening windows might not be as disruptive during these low occupancy times.  Some classrooms have an exhaust fan that can be turned on (usually it makes too much noise to keep on all the time).  Installing heat recovery units (HRVs) can take the heat out of the exhausted air and transfer it to the incoming air to save on energy costs and climate change emissions.  Operating window air conditioners with the outdoor air vent open can bring in more outdoor air during the cooling season (or any season without using the cooling function).  Some fancy systems have CO2 monitors in the ducting system and they can automatically adjust the outdoor air intake rate to reduce the CO2 levels (the Cadillac version). 

Question: My school board says HEPA filters blow the virus around and increase the risk, is this true?

Answer John Oudyk: First of all any fan or blower can blow the emissions from one person’s nose/mouth to another’s breathing zone if it is “aimed” poorly.  The idea is that you blow the air from the ventilation system diffusers, fans, portable air filters so that you don’t blow emissions from one person to another.  Take note, a poorly aimed diffuser in the ventilation system can do this as well, not just fans and portable air filters.  On the other side, a portable air filter takes out particles including particles containing viruses if they are present, and blows out the “cleaned” air and thus reduces the risk.  Now if you don’t maintain the unit as per the manufacturer’s instructions (i.e., replacing the filter), then, yes, when the filter is overloaded or has a poor fit so the air can circumvent the filter, then you might actually be blowing out particles containing viruses from the unit.  However, a properly maintained portable filtering unit which is “aimed” properly will reduce the risk not increase it. 

Question: Where should I place the HEPA filter in my classroom?

Answer John Oudyk: As per the question above, in a place where the unit is not blowing air from one person’s breathing zone to another.  Also, the air intake vent of the unit should not be obstructed.  Placing it under a desk or table will hamper its efficiency.  Be careful not to make it a tripping hazard (one of the actual reasons a school board in Ontario will not allow them in schools). 

Question: If the ventilation isn’t working in my classroom what's the best way to approach the facilities team to put in a maintenance request? I don’t want to mention COVID as it turns them off from even taking me seriously or checking the ventilation.

Answer John Oudyk: This is a H&S strategy question and is highly dependent on who you are dealing with and what motivates them.  I agree, I have taken to referring to the prevention of “respiratory infectious diseases” rather than COVID specifically, which actually, I think is more appropriate.  For some ideas, please see the booklet I referred to in my talk (https://loarc.mcmaster.ca/documents/2016-loarc-workers-guide-1-170609.pdf).  You need to figure out what motivates these people and pitch your request accordingly.  If someone is proud that their system is in compliance, you can ask for evidence of that compliance with ASHRAE 62.1.  If someone is motivated by educational performance, you can show them the studies that indicate better ventilated classrooms translate into better education performance.  Strategically, it’s best to frame your request in their “language”. 

Question: I don't know how to make a CR box are you sharing any videos or instructions with us? 

Answer Let's Clear the Air Representative: We have videos and printable instructions on the Portable Air Cleaning Resources page of the website

Question: Are there new variants circulating that are evading the tests (RATs)?

Answer Joe Vipond: I haven't seen any good science on that. The most current variant is XBB.1.5 aka the "Kraken". We don't seem to be having waves with a single variant anymore so when you get infected with COVID it could be any one of a number of variants. With all the Omicron variants out there now I don't think the science is able to keep up with the immune evasiveness and test evasiveness of these but I am still hearing of people testing positive on them. Loss of sense of smell and taste seems to be COVID specific. Other symptoms can be many other viruses. If you have loss of smell and taste even though testing negative it could be COVID.

Answer Let's Clear the Air Representative: I had COVID 2 weeks ago. Me, my husband and daughter tested positive. My son did not and he was the one that was sick first out of all of us.

Question: Are you still seeing COVID, influenza and other respiratory viruses in the ER?

Answer Joe Vipond: I am still seeing this on every shift, including Long COVID.

Question: When will you stop wearing masks?

Answer Joe Vipond: When there's a sterilizing vaccine.

Answer Let's Clear the Air Representative:  When there's a sterilizing vaccine or a cure for Long COVID. Both my children and myself have Long COVID, we will continue to try to prevent reinfection as the studies coming out show reinfections can make your Long COVIDworse.

Question: How can we support students in the classroom that have fatigue, cognitive impairment, behaviour changes or other bizarre complaints like my muscles hurt after a Covid infection? 

Answer Joe Vipond: The most important thing we can do is validate them.

Answer Angela Grace: I teach comprehensive school health. Teachers don't have to know everything but the most important things teachers can do for students in the classroom that have physical health or mental health issues after a Covid infection are:

• 1. Read as much as you can about the symptoms and impact. The Long COVID Kids Resources page on this website will give you a lot of information.

  2. Cut them some serious slack. Their bodies and brains are reacting to inflammation and organ damage, and they simply can't climb up the ladder to higher level thinking right now. If they need to stay home, send easy homework to keep them busy when they are feeling a bit better. If they are at school but are tired, let them put their head down or do a colouring or art activity, or even listen to music. If they say they have a headache, let them rest. You have to meet them where they are at with kindness. Due to brain inflammation, they might be going through a non-learning day, week, month, or year. 

  3. Remember their physical health comes first. If they don't feel good, they are not going to learn. In that case, it's best to just invite them to participate the best they can, and reassure them that you are there to help them and care for them. Ask them if they are eating and drinking, as they may not be as engaged in body care because they are not feeling well.

  4. Document your observations and communicate them to parents. You are a team that can help give important information to help the child's healthcare team with identifying areas for treatment.

Answer Let's Clear the Air Representative: I would highly recommend attending the Paediatric Post COVID-19 AHS webinars. They are very informative and have lots of great advice. We have them linked on the Long COVID Kids Resources page on the website.

Question: Are there any books I can add to my classroom health library that can help my students with Long COVID?

Answer Angela Grace: There are no specific books about Long COVID and children that I am aware of, however, I would definitely focus on books about antibullying, kindness, emotional regulation, and self-care. Anything promoting positive well-being and relationships will be great.

Answer Let's Clear the Air Representative:  Some of our family's favorite children's books are:

• 1. Sticky Brains by Nicole Libin is great for children that develop anxiety or other intrusive/negative thoughts due to post covid brain inflammation.

  2. Listening to My Body by Gabi Garcia is great to help children understand different sensations and emotions.

  3. Kindness Makes Me Stronger by Elizabeth Cole teaches children how to be kind to others.