Regarding patent: PCT/IB2020/053346
I have found several kinds of millimetric-size UV-C lamps having a price of $2-$4 (retail) that makes
the implementation of this kind of respirator commercial and enough small. output power is several watts. on the other hand laser and LED UV C emission doesn't produce emission.
https://www.alibaba.com/product-detail/Ultraviolet-Germicidal-Tube-H-Shape-12mm_60753152247.html?spm=a2700.details.deiletai6.6.6a5cvIyhvIyhYS