We use UV lights to sanitize medical equipment already. I’ve heard of some offices implementing some UV solutions for cleaning desks and other office surfaces, but nothing new since. Why aren’t we using it in more places? It seems to me to be a cost effective, chemical free, generally *easy* way to disinfect surfaces and objects.
Some examples I thought of would be inside of a refrigerator. These can be full of germs if not properly and regularly cleaned (which many people don’t do) so why not have a UV bulb in there that turns on for a few seconds after the doors close? Or even a cycle that can be scheduled to run each night?
Another would be under cabinet lights in a kitchen. Kitchen counters can be notorious bacteria breeding grounds (the vast majority of food poising cases come from within your own home after all) so why not have some UV light strips underneath that could annihilate all the bacteria automatically?
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In the places you are thinking of, just disinfection isn’t sufficient. There is physical soil and grime that need to be wiped away as well. So if I’m cleaning the fridge your way I have to use my $5 bottle of soap/spray and paper towels first and then your likely very expensive UV light. If this is my house I have to own this thing myself because it’s way more trouble to share one between neighbours. And a $5 bottle of disinfectant is plenty sufficient for six months of cleaning the fridge and other surfaces. We only really need to disinfect surfaces where we’re going to place things that are going to go in our bodies, which isn’t most surfaces in a home.
I’m in construction, specifically office building renovation and construction, and have a lot of first hand experience in the actual products and science being marketed in this area at the moment.
Here are some basic reasons why UV is used extensively or not used –
1. UV needs direct exposure, even a thin layer of dust can reduce it’s effectiveness. Think about your office desk – your keyboard, your mouse, mouse pad, monitor, wires, papers, etc. All of these objects at a minimum cast shadows below which are not being properly exposed to the UV. Sure, you can move things around and clean them, but in that case you can just clean with sanitizing sprays like we already do, no need to spend extra on UV lighting.
2. UV is dangerous for humans. At a minimum OSHA and various international health agencies get involved. In many jurisdictions UV would fall under the same laws as medical radiation – doors need to lock, alarms and timers need to sound, people need to be excluded. That just kind of sucks. to get around this you’ll hear about things like “UV-C” which is the least damaging form of UV light to humans, but also to microorganisms. So it takes longer.
3. UV takes time to sanitize, at least a few minutes of direct exposure. Putting UV in things like Air Ducts is silly because air moves very quickly in ducts, you’re not getting an effective dose on any given portion of air.
4. UV is being used where it’s great! For example, we can use UV on things like filters and water tanks, places where harmful germs grow and thrive and also generally don’t mix around much. In fact, it’s an energy saver as microorganism growth is a large cause for filters getting blocked and causing increased energy to push air through. By slowing that growth you can reduce your energy consumption in your HVAC systems AND keep people healthier. This is absolutely a use for UV and it IS being implemented fairly widely.
UV sterilization works because the radiation corrupts DNA.
Problem is, the radiation doesn’t care if the DNA it corrupts is viral, bacterial or human.
Any light between 100-400nm which comprises UV-A, UV-B and UV-C, can break down DNA at a cellular level, and is the primary cause of skin cancer. The biggest reason you don’t see it commonly used to disinfect is the potential for people nearby to get blasted with UV and develop a sunburn or worse.
There are however systems that use UV to treat air coming out of vents acting as a germ filter, there are UV systems paired with occupancy sensing that only come on when it is sure there is nobody in there, and a tech that has taken off since COVID became a thing is 405nm lighting systems that are just outside of the dangerous level for humans but are still effective against single celled organisms.
They are becoming more common in medical, educational and public service facilities but you won’t be able to tell the difference between a 405nm light and a regular one by design.
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