# If far-UV is so great, why isn't it everywhere?

*Crossposting this essay by my friend* [*Gavriel Kleinwaks*](https://forum.effectivealtruism.org/users/gavriel-kleinwaks)*~~, who is approximately the world expert in Far UV deployment~~.*

*\[Edit: Austin is very kind--I am not close to being the world expert in far UV deployment; there are people who run/used to run companies trying to do that, and researchers who work with them very closely, who know more about far-UV deployment, and I'm largely consolidating information from them. -Gavriel\]*

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*Disclaimer: In the interest of avoiding the problem where a post languishes in drafts forever, I am not attempting to be particularly rigorous, but I’m happy to answer questions to fill in details about how I’ve come to the conclusions I’m writing about. This post is informed by my work experience at 1Day Sooner, but only reflects my personal takes, not the official stance of my organization.*

I work on indoor air quality to reduce disease burden and pandemic risk, and far-UV is an extremely promising intervention. One of the questions I get most often is, “If this is so promising, why isn’t it everywhere?” The answer requires a lot of breakdown and I get a lot of follow-up questions as soon as I start to answer, so this post is an attempt to run through the entire conversation at once. I’d never actually get around to posting this if I also included a deep dive on far-UV or tried to prove its value, so if you don’t know yet why it’s promising, you can check out [this report](https://drive.google.com/file/d/1zAdJpnK9bItjvSPH2txXSQ8VL5IMHuA4/view?usp=drive_link).

**Top line takeaway: Far-UV isn’t widely used because no individual organization has the incentive or bandwidth to install it, and the industry is stuck in a vicious cycle, making companies unreliable. Filtration is already widely used, but more user-friendly filters would greatly improve implementation.**

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**Q: What are the major roadblocks to widespread use of high-quality filters?**

A: The market is hard for consumers to navigate; it’s difficult for consumers to be well-informed enough to assess which filters are high-quality. For example, ionizers (ozone producing and, according to some researchers, basically ineffective[^1^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-1-148547531)) and portable HEPA filters (no harmful byproducts, universally agreed to be useful) are both sold as “air purifiers.”

**Q: What are the major roadblocks to widespread use of far-UV?**

A: 

1.  Far-UV is not intuitive to most people (since other forms of UV are directly harmful to interact with), and people responsible for improving air quality in a given public space may not have the bandwidth to pursue hard-to-understand options over easy-to-understand options like filters.
2.  Far-UV does not have an immediately visible or easily measured impact on a given space, whereas filters can be immediately shown to remove particulate matter from the air using a standard particle counter. Since far-UV only addresses pathogens and not other airborne pollutants, its effect isn’t immediately visible.
    1.  Reduction in disease transmission is very difficult to measure in one specific setting, because people in that setting can get sick elsewhere. This difficulty also means that the benefits of air cleaning are diffuse, but the costs are concentrated. In other words, setting-specific disease reduction has positive externalities, and its impact is most clear in a closed environment or an area where air cleaning tech has been installed in lots of individual buildings simultaneously.
    2.  Businesses want a cost-benefit analysis for the use of far-UV, but a good cost-benefit analysis is impossible to produce without better evidence of real-world disease reduction.
3.  (EDIT 12/13/2025: [Aerolamp](https://aerolamp.net) is a new option on the market! Thanks to Jeff Kaufman for [posting about it](https://forum.effectivealtruism.org/posts/oiPhmbXDomnzKujg4/you-can-just-buy-far-uvc).) There are very few providers, and hardly any of them sell an off-the-shelf product. You usually can’t just buy a lamp to try it out—you have to call the company, get a consultation, and often have someone from the company come install the lamp. It’s a lot of overhead for an expensive product that most people have never heard of.
4.  It could be that even after far-UV is installed, it is only a good idea to have the lamps on at certain times and not others—for example, far-UV might have a harmful photochemical effect on a particular cleaning product, which would warrant the lamps being turned off during cleaning times, until the product dissipates.[^2^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-2-148547531)

**Q: Okay, sounds like more real-world research is needed on far-UV. What are the major roadblocks to that research?**

A: 

1.  Research is very expensive!
2.  People don’t want to feel like part of an experiment. When you ask people[^3^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-3-148547531) to run an experiment in an environment that they occupy, in which you’d install far-UV *for* the experiment, they get worried about it and ethical approval is more difficult to achieve.[^4^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-4-148547531) Hypothetically you can circumvent that problem by finding organizations that want far-UV anyway, and ask to measure the outcome of the installation,[^5^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-5-148547531) but then we get back to the problem of organizations wanting proof that the far-UV is worth their time/money/effort.
3.  Far-UV companies are historically unreliable or short-lived, which is a disaster for study planning. Far-UV companies that we have encountered are typically on the brink of failure, so by the time ethical approval and funding for a study has been successfully arranged, your intended supplier might have gone out of business. Some suppliers also produce low-quality lamps, which may not actually output their purported power, and are therefore less effective than anticipated.
4.  All of the above means that studies are difficult to power—it’s hard to get enough people into any one study with high-quality lamps at the right time.

**Q: So far-UV is facing a vicious cycle. What differences in the state of the world would break the cycle—i.e. What’s your wish list?**

A:

1.  A **reliable** source of off-the-shelf, low-cost, **high-quality** lamps with an **attached ozone scrubber**[^6^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-6-148547531): the ozone produced by high-power lamps is probably the greatest safety concern of far-UV, so having the attached ozone scrubber would eliminate some installation complexity, and a reliable company producing easy-to-install lamps would reduce overhead and confusion on the part of people responsible for ordering the lamps.
    1.  Such a company would probably have to run as a nonprofit for a long time. There is very little technical difficulty to producing this type of lamp, and there is a nonprofit organization in the process of building it,[^7^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-7-148547531) but they are extremely bandwidth-constrained.
2.  Large research investments in clinical trials for far-UV efficacy in **high-control settings**:  high-power clinical trials would probably inspire enough investor confidence[^8^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-8-148547531) to support a more robust far-UV market (although it would not necessarily solve the externality problem).
3.  Large investment in far-UV installations and data collection across **many public buildings in a concentrated area**, e.g. all non-residential buildings in a college town: this type of installation would address the externality problem and deliver real-world data.
4.  Large research investments in far-UV safety/photochemistry: concern about photochemical byproducts of far-UV is probably the main reason that far-UV does not have the full support of the research community. We already know that far-UV installations should happen only in environments with good ventilation, but for ease of communication, we want to be able to provide better-informed guidance on the ventilation rate.
5.  A high-profile installation: an installation at a large well-known company, or funded by such a company, could set trends for other organizations. (“If Google gets far-UV, we want it too!”)
    1.  To support such installations, it would be useful to have a highly visible certification for “healthy air” in a way that references pathogen concentration, analogous to LEED certification, possibly an expansion of the WELL standard.
    2.  One problem is that the ideal flagship adopters are the exact companies that have already invested heavily in high-quality air, and are reluctant to invest more without a great cost-benefit proposition.  

**Q: If you need big research funders or a high-profile installation, why not try to start a government research program? This seems like exactly the sort of thing they do.**

A: The American government is institutionally conservative/risk-averse and we have heard from government offices that they want to see more excitement from the private market before initiating their own investments[^9^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-9-148547531) in research. However, we really hope that governments get excited about far-UV eventually. One very reasonable outcome would be for us to find, through careful research and statistical analysis, that far-UV is almost never worth it for individual private-sector actors to use in peacetime, but that far-UV is invaluable during a pandemic. If that is the case, it would be important for the government to stockpile far-UV lamps and pay for their widespread installation, to only be turned on in the event of a pandemic.

**Q: Are there any good standard-setters outside of the government?**

A: America’s authoritative voice on indoor air quality is the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE). They have no regulatory authority, but their standards are used and referenced by many other organizations, and some building codes require compliance with ASHRAE standards. As a professional association of HVAC engineers, the general body of ASHRAE doesn’t have much epidemiological expertise and isn’t traditionally focused on disease reduction. The COVID pandemic brought indoor air quality to the forefront of epidemiology, so ASHRAE has had more interest in disease reduction, but their standards still focus on HVAC interventions and do not provide guidance on the use of germicidal UV.  

**Q: If ionizers produce ozone and have mixed evidence for their efficacy, why aren’t they facing the same market issues as far-UV?**

A: This question keep me up. Far-UV manufacturers will say that it’s because ionizer companies are better at sales, have bigger backers, and are more willing to use dishonest sales tactics, but that only kicks the question back to why far-UV companies are worse at sales and lack these same large backers as ionizer companies. I have no direct experience of ionizer companies’ sales tactics, but my experience with far-UV sales is that, *in general*, salespeople communicate very differently from researchers in ways that can read as dishonest, and that the field of far-UV is not uniquely virtuous about communication style when business is on the line. I believe that the success of ionizers has more to do with their purported use for eliminating other pollutants (not just pathogens) from the air, so consumers view them as an all-purpose air cleaner. Ionizers also started being marketed for home use in the mid-1900s, before the health concerns of ozone inhalation became widely known, so it’s possible that ionizers were just a well-timed product, and that now their use might slowly die off.

**Q: Do you have a wish list for filtration?**

A: Filtration doesn’t face the same hurdles as far-UV in terms of the vicious cycle relationship between research, market adoption, and government investment, and because it has benefits aside from pathogen reduction. We only spend so much time talking about far-UV because it takes longer to explain as a technology and because the adoption problem is so complicated. The problems with filtration are already being addressed by other parties, who have much greater comparative advantage in this area, so filtration doesn’t “need” 1Day Sooner. My wish list for filtration, which is already well underway, is:

1.  Quieter filters: fan noise is one of the largest problems for filter use, because people get annoyed and turn them off. CleanAirKits already makes a great one, and I hope they conquer the air filter world.[^10^](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-10-148547531)
2.  Cheaper “smart” filters: high-quality filters that include useful features, like automatically adjusting fan speed in response to air quality conditions, are expensive. Smart features reduce the chance that someone will turn off the filter and forget to turn it back on. There are clear market incentives for smart filters to hit a price floor, and we already know a couple of people working on it.
3.  Better public understanding of HEPA filters’ benefit over ionizers: this is hard to tackle because it’s such a diffuse problem, but experts talk about it as much and as widely as they can, and government materials, informed by these researchers, already endorse HEPA filters over ionizers. Another route, which California may take soon, is banning ionizers outright. 

*I may add to/edit this list as more questions occur to me or as I learn more about the far-UV market. Thumbnail image from* [*this biodefense meeting*](https://biodefensecommission.org/events/masters-of-the-air-overcoming-airborne-pathogens-indoors/) *because I thought it was funny.*

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[1](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-1-148547531)

Personal communication with multiple researchers. I have not personally reviewed the literature—a quick glance shows research that seems to both prove and disprove the usefulness of ionizers, but generally I trust the researchers who I spoke with. As a history note, a coalition from the ionizer industry once sued a large group of air quality researchers over publishing research with negative outcomes.

[2](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-2-148547531)

Chamber studies can help address this type of uncertainty, but imperfectly—it’s hard to set up a chamber that imitates all the factors you’d want to consider, such as molecules’ diffusion or deposition. These factors might make far-UV look riskier than it really is, or they might mean that important considerations are missed.

[3](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-3-148547531)

Personal communication with a researcher who tried this avenue.

[4](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-4-148547531)

A study in nursing homes in Nova Scotia has been approved and is currently underway; the entire field is breathlessly awaiting results.

[5](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-5-148547531)

Yeah, this feels a bit like a distinction without a difference to me.

[6](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-6-148547531)

Corollary question that I get because of living in San Francisco amid the starry-eyed tech adventurers and entrepreneurs-by-temperament: If I think that having a reliable far-UV lamp is necessary, why don’t I go found a startup about it?

On the personal fit side, I’m just not that driven to found a startup. It’s not my comparative advantage and I don’t think I’d enjoy it that much—but who knows. As for the field itself, far-UV hasn’t made anyone any money yet; hence the existing companies being constantly on the brink of going out of business. Anyone getting into this field would have to just commit to eating a very large loss that I am not willing to contend with. This type of coordination problem definitionally can’t be solved by the market. (I definitely *hope* that this line of business becomes profitable; just describing the current state of affairs.) Plus, engineering in the physical world has very high overhead—if I wanted to work on the mechanics of far-UV, I’d just go work for the nonprofit working on that and increase their bandwidth and help them work faster, rather than start from scratch to figure out manufacturing best practices and whatnot. (Of course, this very much relies on my belief that the nonprofit in question is good at what they do—people in other industries may very well see many more opportunities to fix things that other people in the field are doing wrong.)

That all being said, I very much believe that the entire far-UV field shouldn’t rest on the shoulders of one or two manufacturers, so if you are a mechanical engineer digging around for new challenges and you’re not put off by everyone else’s failure to turn a profit, I’d be enthusiastic about your building a lamp and would do my best to help you get in touch with people you could learn from.

[7](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-7-148547531)

Personal communication with the group.

[8](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-8-148547531)

Personal communication with an industry sales rep. We were discussing a large but low-control study that some researchers were preparing, and he was pretty scared that it would show no effect. I was surprised to hear that he considered scientific literature so paramount to his business, because I figured that potential buyers never read the scientific literature anyway, but he told me that the decision-makers, like facilities managers, work with engineers who *do* read the literature, and that investors and research grantors do too, and null results make them disinclined to invest or fund higher-control research.

Why run low-control studies anyway? They can be much less expensive (depends on the setting) and they’re more reflective of real use!

[9](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-9-148547531)

Ironically, government research and a government standard would probably make everyone else in the private sector feel a lot better about far-UV! While navigating this field, it has felt like each group is waiting for the other to move first.

[10](https://strainhardening.substack.com/p/if-far-uv-is-so-great-why-isnt-it#footnote-anchor-10-148547531)

Corollary: it might be that one good use of philanthropic money would be to heavily subsidize and distribute ClearAirKits filters, or take out a massive ad campaign for them. My guess is that such a project wouldn’t meet an EA funder bar, but would be good for some major public health funder that likes local/immediate community work, like Chan Zuckerberg. I have not researched this carefully.