7 ms·

When you talk to Indoor Air Quality (IAQ) most are uncomfortable with UV. Reason being that while you can get rid of viruses, you can also create volatile compo

by a1371 4y ago

When you talk to Indoor Air Quality (IAQ) most are uncomfortable with UV. Reason being that while you can get rid of viruses, you can also create volatile compounds. Our homes' air is like a soup of natural and synthetic chemicals. From your flooring wear to your decor off-gassing to cooking, there are elements in your air that may be safe as they are, but they can completely change when they hit something volatile like ozone (from cars). Subsequently there can be a chain reaction with other compounds, potentially causing particles in your air that are bad for your health. If you could see that with magical glasses it would seem as if there are fireworks happening in your air triggered by those volatile compounds. So while UV has clear benefits, the byproducts that the lab conditions usually don't catch, make the applications limited.

bradknowles 4y ago
Most quality whole-home HEPA air filters I know of are available with UV lights that can be added to the mix to further help reduce the viral load in the house. And excessive ozone production is specifically avoided. For those units, I don't think there's anything to be concerned about here, except the added cost of the UV lighting and what might happen if you (or a technician) were accidentally exposed to the UV lighting during maintenance of the equipment. IMO, you're going to have to provide some extraordinary evidence if you want to claim UV health risks beyond these two factors.
wesapien 4y ago
My uncle has ozone generators in his home. One of them is industrial strength and he only runs it when he is leaving his house for awhile. Does ozone produce by products? I vaguely recall hospitals used ozone to clean n95 masks.
- colechristensen 4y ago
  Ozone itself is the main culprit.
- yummypaint 4y ago
  I think it's pretty well established that ozone can interact unpredictabily, especially with chemically complex modern building materials. Here is one anecdotal example: https://www.reddit.com/r/homeowners/comments/d2rjsb/ozone_generator_left_a_bad_odor/ https://www.reddit.com/r/homeowners/comments/d2rjsb/ozone_ge... N95 masks actually seem like one of the few use cases that make sense, as their composition is well known and they can be easily enclosed. Even when ozone generators work as expected, they can take months to remove odors from spaces.
- solarist 4y ago
  See here: https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-are-sold-air-cleaners https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-... At the end I decided against the ozone generator for my home and went instead for an air purifier with filter.
- slimsag 4y ago
  Ozone is very dangerous. The EPA concluded it poses serious health risks back in 2013 (causes asthma and respiratory harm, short and long term exposure is linked to likely early death, and even linked to cardiovascular problems.) Cleaning air is simple; you don't need to look to obscure Ozone/UV devices. For gasses/VOCs, you need a carbon filter. The larger the filter and more air that moves past it, the better. You can grab industrial ones used in greenhouses for ~$150, some brands (LAYOND on Amazon) have cases that make them look alright and make them quiet. For particulate (dust), a carbon filter works OK but a HEPA filter is better. Get a name brand one (Honeywell) so you're not getting ripped off. None of that will replace the lack of oxygen, though-so open a window.
  - saurik 4y ago
    > None of that will replace the lack of oxygen, though-so open a window. I would think that it would be really hard to make any kind of dent in how much oxygen is in the room... wouldn't, by the time you get there, you have long long since died of carbon dioxide poisoning?
    - wincy 4y ago
      Just small increases in the CO2 concentration can cause brain fog and headaches even if you won’t literally die from the room. Normally the feeling of a room being “stuffy” is the first sign. That’s a mere 600ppm where that begins to happen. Here’s the basic levels of CO2 that are acceptable in a room. I know I get drowsy in rooms without good airflow when in meetings at the office. https://www.engineeringtoolbox.com/amp/co2-comfort-level-d_1024.html https://www.engineeringtoolbox.com/amp/co2-comfort-level-d_1...
      - _benedict 4y ago
        And yet in not many years that will be atmospheric levels. This is the element of fossil fuel emissions nobody seems to be discussing, and we don’t know its consequences
      - ajuc 4y ago
- deleted 4y ago
  [deleted]
- Fomite 4y ago
  Ozone is used in some hospitals, but in fairly intense concentrations and in unoccupied rooms, generally. UV, Ozone and vaporized hydrogen peroxide are all used to some extent. None of them in ways I'd recommend for the home.
clumsysmurf 4y ago
Interesting, does this also apply to far-UVC (222nm)? Its not surprising that UV would be a catalyst in some undesirable scenario. I'm thinking about toxic residues left by cigarette smoking reacting with household surfaces. Research suggests that rooms facing the sun (with blinds open) have less bacteria and viruses because it is a disinfectant. I would have to imagine in many homes, UV is somewhat pervasive anyhow. https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-018-0559-4 https://microbiomejournal.biomedcentral.com/articles/10.1186...
- raverbashing 4y ago
  Yeah While glass blocks some of UV light I'm not sure it would be a big problem. Especially if it's constrained to a tube, for example Couple it with an activated carbon filter and it should be good (also a HEPA filter of course)
  - highwaylights 4y ago
    You can buy HEPA units that have a strip of UV diodes internally after the filter. They’re not overly expensive units. The idea being that the air will pass through: Charcoal (activated carbon) -> HEPA media -> UV light. There are some arguments that the UV stage might lower air quality by causing particulates to adhere to room surfaces due to electrostatic charge (i.e. particulate counts would drop rapidly due to particles sticking to walls and furniture, but would then drop off as the charge dissipates and return to room air after the filter is off). I’m not sure how relevant this is - as the filter would catch the particles on the next cycle so I guess it would depend on if the unit is running 24/7 or only some of the time. Mine failed under warranty and wasn’t replaced with a UV unit due to concerns about Ozone.
  - Khelavaster 4y ago
    Doesn't bacteria break down in activated carbon and release VOOCs?
DoingIsLearning 4y ago
When you mention decor off-gasing, is this the whole thing about off-gasing fire retardant chemical treatments? Or did you mean another source in household stuff?
- nerdawson 4y ago
  I think pressed / laminated sheet materials like particleboard are one of the biggest sources of offgassing in many homes.
  - DoingIsLearning 4y ago
    So it's mostly volatile stuff coming out of the glues in particleboard?
jansan 4y ago
I have a cheap UV-C lamp that I purchased from ebay. Aside from the danger to your skin and eyes, after running for a few minutes there will be a distinct ozone smell in the room. Once I keept it on for a few hours in a small room (windows and door closed, no people inside). The ozone smell was still there after one week. So at least the lamp that I own would not be suitable for killing virii in indoor environments, unless there is an easy way to convert the ozone back to O2.
- mensetmanusman 4y ago
  If a cheap UV lamp doesn’t have a sub 200 nm absorber layer, it will generate orders of magnitude more ozone than it should: https://www.uvccleaningsystems.com/cm/dpl/downloads/content/1107/Ozone-222nm_lamps.pdf https://www.uvccleaningsystems.com/cm/dpl/downloads/content/... Be wary of cheap electronics. E.g. People have been blinded by green laser pointers that convert 1064 nm IR light because of removed ir blocking filters that certain low cost manufacturers remove out of ignorance.

by a1371 4y ago

bradknowles 4y ago

Most quality whole-home HEPA air filters I know of are available with UV lights that can be added to the mix to further help reduce the viral load in the house. And excessive ozone production is specifically avoided. For those units, I don't think there's anything to be concerned about here, except the added cost of the UV lighting and what might happen if you (or a technician) were accidentally exposed to the UV lighting during maintenance of the equipment. IMO, you're going to have to provide some extraordinary evidence if you want to claim UV health risks beyond these two factors.

wesapien 4y ago

My uncle has ozone generators in his home. One of them is industrial strength and he only runs it when he is leaving his house for awhile. Does ozone produce by products? I vaguely recall hospitals used ozone to clean n95 masks.

colechristensen 4y ago
Ozone itself is the main culprit.
yummypaint 4y ago
I think it's pretty well established that ozone can interact unpredictabily, especially with chemically complex modern building materials. Here is one anecdotal example: https://www.reddit.com/r/homeowners/comments/d2rjsb/ozone_generator_left_a_bad_odor/ https://www.reddit.com/r/homeowners/comments/d2rjsb/ozone_ge... N95 masks actually seem like one of the few use cases that make sense, as their composition is well known and they can be easily enclosed. Even when ozone generators work as expected, they can take months to remove odors from spaces.
solarist 4y ago
See here: https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-are-sold-air-cleaners https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-... At the end I decided against the ozone generator for my home and went instead for an air purifier with filter.
slimsag 4y ago
Ozone is very dangerous. The EPA concluded it poses serious health risks back in 2013 (causes asthma and respiratory harm, short and long term exposure is linked to likely early death, and even linked to cardiovascular problems.) Cleaning air is simple; you don't need to look to obscure Ozone/UV devices. For gasses/VOCs, you need a carbon filter. The larger the filter and more air that moves past it, the better. You can grab industrial ones used in greenhouses for ~$150, some brands (LAYOND on Amazon) have cases that make them look alright and make them quiet. For particulate (dust), a carbon filter works OK but a HEPA filter is better. Get a name brand one (Honeywell) so you're not getting ripped off. None of that will replace the lack of oxygen, though-so open a window.
- saurik 4y ago
  > None of that will replace the lack of oxygen, though-so open a window. I would think that it would be really hard to make any kind of dent in how much oxygen is in the room... wouldn't, by the time you get there, you have long long since died of carbon dioxide poisoning?
  - wincy 4y ago
    Just small increases in the CO2 concentration can cause brain fog and headaches even if you won’t literally die from the room. Normally the feeling of a room being “stuffy” is the first sign. That’s a mere 600ppm where that begins to happen. Here’s the basic levels of CO2 that are acceptable in a room. I know I get drowsy in rooms without good airflow when in meetings at the office. https://www.engineeringtoolbox.com/amp/co2-comfort-level-d_1024.html https://www.engineeringtoolbox.com/amp/co2-comfort-level-d_1...
    - _benedict 4y ago
      And yet in not many years that will be atmospheric levels. This is the element of fossil fuel emissions nobody seems to be discussing, and we don’t know its consequences
    - ajuc 4y ago
deleted 4y ago
[deleted]
Fomite 4y ago
Ozone is used in some hospitals, but in fairly intense concentrations and in unoccupied rooms, generally. UV, Ozone and vaporized hydrogen peroxide are all used to some extent. None of them in ways I'd recommend for the home.

clumsysmurf 4y ago

Interesting, does this also apply to far-UVC (222nm)? Its not surprising that UV would be a catalyst in some undesirable scenario. I'm thinking about toxic residues left by cigarette smoking reacting with household surfaces. Research suggests that rooms facing the sun (with blinds open) have less bacteria and viruses because it is a disinfectant. I would have to imagine in many homes, UV is somewhat pervasive anyhow. https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-018-0559-4 https://microbiomejournal.biomedcentral.com/articles/10.1186...

raverbashing 4y ago
Yeah While glass blocks some of UV light I'm not sure it would be a big problem. Especially if it's constrained to a tube, for example Couple it with an activated carbon filter and it should be good (also a HEPA filter of course)
- highwaylights 4y ago
  You can buy HEPA units that have a strip of UV diodes internally after the filter. They’re not overly expensive units. The idea being that the air will pass through: Charcoal (activated carbon) -> HEPA media -> UV light. There are some arguments that the UV stage might lower air quality by causing particulates to adhere to room surfaces due to electrostatic charge (i.e. particulate counts would drop rapidly due to particles sticking to walls and furniture, but would then drop off as the charge dissipates and return to room air after the filter is off). I’m not sure how relevant this is - as the filter would catch the particles on the next cycle so I guess it would depend on if the unit is running 24/7 or only some of the time. Mine failed under warranty and wasn’t replaced with a UV unit due to concerns about Ozone.
- Khelavaster 4y ago
  Doesn't bacteria break down in activated carbon and release VOOCs?

DoingIsLearning 4y ago

When you mention decor off-gasing, is this the whole thing about off-gasing fire retardant chemical treatments? Or did you mean another source in household stuff?

nerdawson 4y ago
I think pressed / laminated sheet materials like particleboard are one of the biggest sources of offgassing in many homes.
- DoingIsLearning 4y ago
  So it's mostly volatile stuff coming out of the glues in particleboard?

jansan 4y ago

I have a cheap UV-C lamp that I purchased from ebay. Aside from the danger to your skin and eyes, after running for a few minutes there will be a distinct ozone smell in the room. Once I keept it on for a few hours in a small room (windows and door closed, no people inside). The ozone smell was still there after one week. So at least the lamp that I own would not be suitable for killing virii in indoor environments, unless there is an easy way to convert the ozone back to O2.

mensetmanusman 4y ago
If a cheap UV lamp doesn’t have a sub 200 nm absorber layer, it will generate orders of magnitude more ozone than it should: https://www.uvccleaningsystems.com/cm/dpl/downloads/content/1107/Ozone-222nm_lamps.pdf https://www.uvccleaningsystems.com/cm/dpl/downloads/content/... Be wary of cheap electronics. E.g. People have been blinded by green laser pointers that convert 1064 nm IR light because of removed ir blocking filters that certain low cost manufacturers remove out of ignorance.