Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Germicidal UV could make airborne diseases as rare as those carried by water

worksinprogress.news

Post reply on HN
Print view View original

11–20 of 70 posts

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#11

Post by mahrain »

toast0 wrote: post #9

Seems like this has potential, but uv exposure is potentially problematic to humans, and definitely problematic to man surfaces and some plants. Limiting the wavelength helps with humans, but adds a lot of cost. It might be effective to have a box that draws in air (with a fan, most likely) and the UV source shines within. The inputs and outputs would need to have a few turns and have surface treatments to reduce the…

This is correct and such systems do exist, sometimes combined with sources of ions and HEPA filters. However if you're already drawing air out of the room, it's easier to just filter it with HEPA than dealing with the additional complexity of UV lights (deterioration, energy consumption, replacement).

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#12

Post by mahrain »

unsnap_biceps wrote: post #10
mahrain wrote: post #6

I have worked on such systems at Signify: There are numerous barriers to wider adoption except for very high risk situations. For instance: there have yet to be lawsuits to determine the risk of exposing people to UV. As you see in the comments below, any "UV" is considered dangerous by people not aware of the biological effects of various wavelenghts. Besides this, excimer lamps have a low expected lifetime, of both…

Every year our HVAC company tries to sell us UV lights for the HVAC system. They claim it's only about $1500 to install. Are these snake oil?

Mostly used to eliminate or reduce mould growth on the inverter? If HVAC is taking air in or blowing air out, there really wouldn't be a point disinfecting the air.

If it's re-circulating, it could reduce the spread of germs room to room as has been shown during the pandemic in elderly care facilities. That would be the only use-case I see.

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#13

Post by unsnap_biceps »

mahrain wrote: post #12
unsnap_biceps wrote: post #10

Earlier quoted context omitted.

Every year our HVAC company tries to sell us UV lights for the HVAC system. They claim it's only about $1500 to install. Are these snake oil?

Mostly used to eliminate or reduce mould growth on the inverter? If HVAC is taking air in or blowing air out, there really wouldn't be a point disinfecting the air. If it's re-circulating, it could reduce the spread of germs room to room as has been shown during the pandemic in elderly care facilities. That would be the only use-case I see.

they claim it would reduce growths on the coils but also eliminate mold and bacteria spores. Our system is a re-circulating system. One large intake in the center of the house and out flows in individual rooms.

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#14

Post by modeless »

mahrain wrote: post #6

I have worked on such systems at Signify: There are numerous barriers to wider adoption except for very high risk situations. For instance: there have yet to be lawsuits to determine the risk of exposing people to UV. As you see in the comments below, any "UV" is considered dangerous by people not aware of the biological effects of various wavelenghts. Besides this, excimer lamps have a low expected lifetime, of both…

Yeah I saw a lamp for this and it had a proximity sensor to prevent overexposure. There's no way I'm buying a lamp that needs that to be safe. Especially if it's expensive and only lasts a year or two.

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#15

Post by mahrain »

unsnap_biceps wrote: post #13
mahrain wrote: post #12

Earlier quoted context omitted.

Mostly used to eliminate or reduce mould growth on the inverter? If HVAC is taking air in or blowing air out, there really wouldn't be a point disinfecting the air. If it's re-circulating, it could reduce the spread of germs room to room as has been shown during the pandemic in elderly care facilities. That would be the only use-case I see.

they claim it would reduce growths on the coils but also eliminate mold and bacteria spores. Our system is a re-circulating system. One large intake in the center of the house and out flows in individual rooms.

The mould reduction is real, and could lenghten the maintenance intervals for cleaning. Not fully eliminate it though, it really only eliminates the parts the UV light reaches (so not the back, or any other part not exposed).

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#17

Post by vintermann »

No mention of ozone. The more directly dangerous 254nm UV light has the advantage that it doesn't create ozone.

Viruses and bacteria aren't the only bad things you don't want in your air. Ozone is thought to be a carcinogen in its own right and aggravate the health effects of particulate pollution. We want filtering and air circulation anyway, we don't want anything that makes it worse. The consumer electronics industry is all too willing to try to sell us things that make our problems worse, such as ultrasonic humidifiers, or ionizing air purifiers with special chambers for your aromatherapy oils, so it's best to be careful.

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#19

Post by schiffern »

mahrain wrote: post #11
toast0 wrote: post #9

Seems like this has potential, but uv exposure is potentially problematic to humans, and definitely problematic to man surfaces and some plants. Limiting the wavelength helps with humans, but adds a lot of cost. It might be effective to have a box that draws in air (with a fan, most likely) and the UV source shines within. The inputs and outputs would need to have a few turns and have surface treatments to reduce the…

This is correct and such systems do exist, sometimes combined with sources of ions and HEPA filters. However if you're already drawing air out of the room, it's easier to just filter it with HEPA than dealing with the additional complexity of UV lights (deterioration, energy consumption, replacement).

HEPA filters also have deterioration, energy consumption (pressure drop ain't free), and replacement.

HEPA is a mature technology with no big improvement curve, but UV treatment is seeing progress.

Re: Germicidal UV could make airborne diseases as rare as those carried by water

#20

Post by mahrain »

vintermann wrote: post #17

No mention of ozone. The more directly dangerous 254nm UV light has the advantage that it doesn't create ozone. Viruses and bacteria aren't the only bad things you don't want in your air. Ozone is thought to be a carcinogen in its own right and aggravate the health effects of particulate pollution. We want filtering and air circulation anyway, we don't want anything that makes it worse. The consumer electronics indus…

Could accumulate in an isolated room, but following normal building ventilation standards, really shouldn't be an issue as shown by Brenner in 2023: https://pubmed.ncbi.nlm.nih.gov/38037431/
Post reply on HN