Health Canada published new Guidance for Indoor Air Quality (IAQ) Professionals that acknowledge that Covid can be spread through airborne transmission.
"Indoor air quality is considered an important environmental determinant of health. ... Good indoor air can often be achieved using the following three strategies: reducing or eliminating the sources of air contaminants, ventilating by replacing contaminated indoor air with filtered air from outside, filtering the indoor air ... and education of occupants and building staff on best practices for maintaining good indoor air quality. ...
Epidemiological studies on CO2 concentrations and health effects showed that individuals exposed to CO2 concentrations greater than 800 ppm were more likely to report mucous membrane or respiratory symptoms than those exposed to lower CO2 levels. ... Installing demand-based ventilation relying on CO2 sensors may also be an effective strategy. ... Avoid overcrowding indoor environments with more people than the HVAC system can accommodate. Increase natural ventilation by opening windows. ...
The concept of using indoor CO2 levels as an indicator of ventilation has been discussed for decades. With increased public awareness of the importance of ventilation and commercial-availability of CO2 monitors, there is a renewed interest in using CO2 monitoring as a method for quantifying ventilation. ... Continuous measurements can also be used to see how levels change over the course of the day and whether there are certain locations or certain times of day that are more problematic. ...
With some viruses, such as SARS-CoV-2, transmission was also found to occur from particles remaining suspended in the air and travelling longer distances, hence the benefit of wearing masks, effective ventilation and building air filtration, and stand-alone air purifiers that utilize high efficiency particulate air filters when and where appropriate to reduce the risk of transmission. ... There are no exposure limits for the range of microbial agents found indoors that can cause disease, as these are dependent on the infectious dose needed to cause an infection. Levels should be kept as low as possible. ... Effective ventilation is important for reducing indoor transmission of respiratory infectious diseases and includes ... increasing indoor/outdoor air exchange with exhaust fans and mechanical ventilation systems, filtering air efficiently, and opening external windows and doors. Ventilation can help reduce viral transmission in indoor spaces by preventing the accumulation of potentially infectious respiratory particles in the air. Good ventilation, combined with other personal protective measures, can further reduce the risk of infection.
In addition to improving indoor ventilation, the following should be considered: encourage occupants to stay home and away from others if they are not feeling well; limit the amount of people in areas where ventilation if poor; have policies that require or strongly recommend people to wear a well-fitting N95 or KN95 respirator mask in indoor public settings, provide supplies for people to clean their hands often. Remind occupants to clean their hands after contact with shared surfaces and objects, and after coughing or sneezing. ...
Preventing issues before they arise and addressing them as soon as they are identified are the best strategies to maintain acceptable indoor air quality."
The OSPE calls this new guidance "a meaningful step forward, a real policy win for engineers and the public." This is great news, but it's so frustrating that this is only coming now, over five years since I first started researching all this independently, learning more than a non-professional should ever have to know about air flow, four years since my school admin tried to prevent me from putting a CR box in my classroom when post lunch CO2 levels were over 2,000 ppm, and three years since I tried my very best to push for change from the board office. I've had negligible effect over the years. The guidance is a little vindicating, but I still doubt anything will change significantly. We've known all this -- all this time the information was there for the taking -- yet the powers that be do all they can to avoid monitoring CO2 levels in classrooms or filtering the air. We live in crazy times!
ETA, infectious disease expert, Dr. Noor Bari, wrote,
"Yes kids should be wearing masks in schools and being given cleaner air. Those masks should be comfy and cheap. Why? Because kids are getting sick with a disease that we know very little about, and what we do know is looking problematic.
No one wants to say it. It sounds really unreasonable. My kid looks fine! But as health professionals, we have to look deeper and advise better. Kids are getting LongCovid. Repeated infections don't reduce that risk. Blood vessel and brain health are important for longevity. I'm not talking any talk where I/we haven't walked the walk. I'd like everyone's kids to have the choice of better health, the way the privileged kids do. Whether that's financial or knowledge privilege. All the health protections that are available to the most privileged amongst us should. be available for every child because they are our future.
Saying kids should wear respiratory protection is extremely unpopular. I get why, but being sick long term is no fun either. I'd like to give the kids the world I had without Covid-19 running through the classroom twice a year and all the other bugs. I can't. So this is the second best thing.
The absolute worst thing is to pretend we know what we are doing and convince ourselves that playing with a novel virus will be fine. It really might not be. Even if you are in the school of thought that if the kids are still dragging their exhausted bodies and minds to class, they'll be fine. We need to teach kids life skills to manage C19 for the long term, for when they are adults, and then older adults. And we need to teach a way of life that means the most vulnerable amongst them gets to be amongst them. Not isolating, sick, or dead.
If anyone asks me if kids should wear masks, I say 'yes', at least for now. I know that people will think I'm a dreadful person, but my personal feelings about being a social pariah can't dictate the medical advice I give. RIP my mentions."