Nobody will pay you more for cleaner air directly

Tuesday, September 28th, 2021

Alex Tabarrok finds it puzzling that there isn’t more attention given to air filtration and UV light disinfection in hospitals, since these techniques have been shown to kill superbugs:

The authors installed portable air filters with UV disinfection on two COVID hospital wards in the UK. The air was tested for viruses, bacteria and fungi before the filters were turned on, during the time the filters were on and then again after the filters were turned off.

The results:

Airborne SARS-CoV-2 was detected in the ward on all five days before activation of air/UV filtration, but on none of the five days when the air/UV filter was operational; SARS-CoV-2 was again detected on four out of five days when the filter was off.

Importantly, in addition to greatly reducing SARS-CoV-2 the portable filters and UV light also greatly reduced multiple viral, bacterial, and fungal pathogens.

A commenter explains why this hasn’t become common practice already:

The main regulation rests largely on ASHRAE 170-2017. That in turn has been addended over a dozen times since the pandemic began. We have done things to change how air is handled in light of these and the more direct regulators (e.g. the Joint Commission) are adapting.

But it is not trivial to do all of this. Some hospitals have ductwork that is over a 100 years old. Adding in UV creates problems for reactive species in the air. And then there is the problem that any refits (e.g. to handle higher pressures/volumes) often means opening up the ceilings inside the ICUs or going through the floor in the the floor above. These are highly disruptive activities at the best of times. When you are (or may soon) be at or above bed capacity, well not the best time to bring in a small legion of contractors to close large areas of the hospital.

Then, yes, money is a huge thing. Funny thing is, nobody will pay you more for cleaner air directly. You might be able to eke out some sort of capital return through fewer nosocomial infections or uncharged readmissions, but those are speculative returns at this point and pretty long run things when, again, right now beds in many places are still exceptionally highly utilized. Worse, when you do open up the tubes and start mucking around there is a very high risk that you will disturb some collection of spores that has found some dark corner to accumulate in over the last few decades. When you have a bunch folks who already have respiratory compromise, this is a particularly bad time to risk that sort of contamination.

So faced with high upfront costs, a strong litigation risk, and remote cost savings, this is not a priority right now. If you want a massive overhaul of the air system right now it is going to need liability waivers and giveaways to the AHA crowd. A slower roll out via changes in ASHRAE and the like is already underway, but I figure it will be over a decade before everyone updates.


  1. Sam J. says:

    Ding, ding, portable filters with UV lights. I have one of these. It’s very small but it works over time, The air seems much better in my bedroom where I keep it.

    I have a fairly industrial ionizer also. Yikes I’ve turned it up too much before and caused problems. So you have to be careful. On the other hand if you crank that thing up wide open then leave the room until it saturates the whole room. Let it air out for a good while it really cleans the air up.

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