UVC (ultraviolet light) has been used for killing bacteria for decades, but it is not resurgent largely because of Covid. It kills bugs very effectively. The trouble is it it can also be dangerous because doses above certain levels can initiate cancer.
There are a few simple statement that clearly show why UVC is so wonderful if the objective is to kill bacteria, but so dangerous if allowed to hit living matter:
- UVC is not present in our atmosphere – the Ozone layer absorbs it
- UVC attacks and breaks up DNA, which is why it kills bacteria so thoroughly
- Most of the living matter in our bodies reproduces itself according the encoded DNA. If this DNA is broken up by UVC, the body can start reproducing DNA incorrectly, which is effectively what cancer is.
- Dead material, such as the layer of dead skin we all have, protects us from UVC because our bodies don’t try to reproduce it. It doesn’t matter if it is attacked by UVC.
- In order to determine what’s safe it is both the level of UVC and the time that are important. Whilst the dead matter (skin) is being destroyed, we are safe.