Ending airborne disease like we ended waterborne disease
Water-borne illnesses are practically extinct in the developed world. This is a major triumph since these plagued our ancestors in all of human history. But what about airborne illness?
We know that it's possible to eradicate airborne illnesses. In fact, we did this accidentally during COVID. There used to be 4 major strains of influenza, but one of them went extinct during COVID because it couldn't spread during quarantine.
There's a new technology that aims to sterilize air called "far UV-C lamps". I went to a round-table with a few UV-C experts moderated by Patrick McKenzie , and these are my notes.
What is far UV-C?
- Far UV-C is the most energetic type of UV light. It is not found in sunlight.
- Far UV-C is very effective at killing bacteria and viruses. They denature their proteins.
How can they be used?
- Far UV-C lamps can effectively sterilize the air in public spaces that are more likely to transmit airborne pathogens:
- Rooms that high people density, especially where there is low turn-over.
- Rooms where people are exhaling a lot due to singing, exercise, or talking.
- Rooms with poor air circulation, where pathogens can linger for longer.
- Rooms full of sick people.
Questions I had
- Far UV-C doesn't harm eyes or skin. The top-most layer of your skin are dead cells, so it doesn't matter if you denature those proteins. Far UV-C does not penetrate far into your skin, which is why it doesn't cause skin cancer or sunburns like ordinary UV light.
- It does not eradicate your skin flora, which live in the microscopic crevasses of your skin. Similarly, it wouldn't sterilize a cloth sofa because the light cannot penetrate into the folds.
- The lamps are visibly purple, even though Far UV-C is beyond the visible spectrum. This is because the lamps don't purely produce Far UV-C frequencies: the spectra is leaky. So how won't these cause blindness or sunburn? Because the lamps have special filters to block the bad UV.
- They are currently a tad expensive, about $500. However, this can probably be reduced to $50 with economies of scale, and further than that with material science breakthroughs.
Downsides of Far UV-C lamps
- They produce minuscule amounts of ozone. Normal levels outdoors are ~30 and around ~10 inside. With a UV-C lamp on, this increases to ~11-12.
- Certain chemicals interact with Far UV-C and create dangerous byproducts. Two big ones are turpines and lemon-scented cleaning products.
- Turpines react with ozone, stick together, and become uniquely bad nano-particles that embed themselves in your lungs and break your brain.