So, as I am writing this, we are on day N (14 ish?) of COVID-19 / Coronavirus quarantine. To be clear, we are not being quarantined, we’re just being told to stay at home. As we (literally everyone in the world) know, Coronavirus is highly contagious and lives on surfaces, so it seemed like it would be a good idea to build a decontamination chamber for things that we bring into the house… like groceries, mail, packages, shoes, keys, purses, jackets, etc…
Also, the company I work for happens to make ozone destruction catalysts. Ozone is a byproduct of sanitation by UV, but it also is a sanitizer in and of itself. You can bubble it through liquids to sanitize liquids, or pump it into air to sanitize the surrounding things. BUT it is important to note that ozone is a pollutant and is dangerous. It is poisonous, is a component of smog and is carcinogenic. I use an ozone destruction catalyst (scrap from work) to treat the ozone in the stack of my decontamination chamber to mitigate this danger. My ozone chamber is also kept outside.
The antibiotic and antiviral effects of ozone are well documented, for instance here. It works because it is not very stable. The third oxygen (oxygen really would rather be a diatomic molecule) is readily available to oxidize anything it comes across and this is catastrophic for a virus or a bacteria which could hitch a ride on your milk. WARNING: It oxidizes anything and some things, like electronics, can easily be destroyed by it.
TLDR:
- I built an ozone decontamination chamber.
- Ozone is dangerous to human health and shouldn’t be breathed. It’s also bad for the environment. (You can’t even buy ozone generators in California.)
- Ozone is great at oxidizing things. Viruses, Bacteria, iPhones, Rubber. It is a molecule, it is not selective, it does not care about your fancy gadgetry.
The Chamber
The chamber itself is very simple. I found an unused plastic tote in my attic, drilled a small hole the same size as the tube that comes out of the ozone generator and cut a larger hole to fit with the catalyst-filled PVC vent. The catalyst is coated onto a foam substrate which is rolled and fit into the tubes (and is quite snug, this worked great). I had enough to do 2 layers of the rolled catalyst foam. The PVC vent is inserted into the larger hole and secured/sealed with duct tape. So simple! I’m thinking also about incorporating an internal fan so that the ozone is well-distributed throughout.
Here is a close-up of the catalyst-filled vent… there’s foam in there, trust me.
Because the Coronavirus is now community spread in most/many(/all?) areas and it can deposit onto all kinds of smooth surfaces (especially), once items are in a store they can harbor the virus for quite a long time. So, one of our main use-cases for this chamber is to decontaminate food when it comes in from the grocery store. Here is an example on our recent grocery run. We were slightly concerned that there might be residual smell, but that wasn’t the case. There was a slight bleach-like smell after the treatment, but this wasn’t overpowering and dissipated quickly. I let the machine run for 30 minutes and let it sit for an additional hour. The half-life for ozone is (according to my reading) about 20 minutes, so this should allow reduction to 1/8 the maximum level. Obviously this wouldn’t work for ice cream or other frozen goodness.
Important Disclaimers!
- This has not been tested to see how effective it is. Many questions remain with regard to the effective concentration, the required residence time, the durability of the system, and the amount of ozone which can escape.
- This is a personal project and I am not responsible for misuse.
- Ozone generators should definitely not be used in a close space where people breathe!!!!!
- I am very lucky and maybe somewhat unique in my access to ozone destruction catalyst.
- There are no guarantees, implied or otherwise, of its effectiveness in killing the coronavirus.
- I am only guessing based on previous literature that something like this has a chance of working. I HAVE NO WAY TO TEST IF IT ACTUALLY WORKS.
- THIS IS NOT A REPLACEMENT FOR WASHING YOUR HANDS
- Please also frequently clean your door handles and light switches and stay home as much as possible.
That said, I am excited for the time when the clear and present danger has passed and I can use this to make our shoes and sandals less stinky. Things do come out smelling much nicer than when they went in.
Tinkered with love,
Erica