Intesesting article and framing, thank you. I’ve only just got round to reading it but have a few questions.
First, by clean air, do you mean low CO2 or no pathogens? These seem to have quite different solutions and benefits but the article doesn’t cleanly distinguish. Most of the solutions (excepting ventilation) do not reduce CO2 levels, and hence would not give the benefits to cognition etc that ventilation do. Furthermore, monitoring CO2 levels won’t tell you much because, once you implement these solutions, the link between CO2 levels and pathogen levels is broken.
Second, I’m not convinced the evidence supports the size of benefit you suggest here: near-elimination of respiratory illness through clean air alone. The updated 1DaySooner report (which I appreciate wasn’t published when you wrote this piece) estimates reducing transmission by 30--75%. While the mid-to-top-end of that range might remove flu epidemics (R0 up to around 2) as a threat, this seems less likely for all respiratory illnesses such as endemic coronaviruses (R0 around 10) or even original, Wuhan SARS-CoV-2 (R0 at least 3, likely 4 or higher). It certainly wouldn’t be enough for measles (R0 15--20). Indoor air cleaning still seems valuable but I wouldn’t want to oversell it as a silver bullet, rather than one line in multi-factorial pathogen defence.
Intesesting article and framing, thank you. I’ve only just got round to reading it but have a few questions.
First, by clean air, do you mean low CO2 or no pathogens? These seem to have quite different solutions and benefits but the article doesn’t cleanly distinguish. Most of the solutions (excepting ventilation) do not reduce CO2 levels, and hence would not give the benefits to cognition etc that ventilation do. Furthermore, monitoring CO2 levels won’t tell you much because, once you implement these solutions, the link between CO2 levels and pathogen levels is broken.
Second, I’m not convinced the evidence supports the size of benefit you suggest here: near-elimination of respiratory illness through clean air alone. The updated 1DaySooner report (which I appreciate wasn’t published when you wrote this piece) estimates reducing transmission by 30--75%. While the mid-to-top-end of that range might remove flu epidemics (R0 up to around 2) as a threat, this seems less likely for all respiratory illnesses such as endemic coronaviruses (R0 around 10) or even original, Wuhan SARS-CoV-2 (R0 at least 3, likely 4 or higher). It certainly wouldn’t be enough for measles (R0 15--20). Indoor air cleaning still seems valuable but I wouldn’t want to oversell it as a silver bullet, rather than one line in multi-factorial pathogen defence.
Finally, I was wondering if there was a reason you didn’t mention the update to UK building regulations to include indoor air quality (published 2021). These look really promosing to me, although I’m not an expert in either the regulatary or technical side, so would appreciate further commentary!