Just curious…with all this talk of COVID-19, my husband asked if my new FormCure could be used to disinfect something, like a mask.
I saw that the wavelengths of UV light were generally lower for disinfection, like maybe in the 280nm wavelength (don’t quote me on that…I’m a jewelry artist, not an engineer), but is that a minimum wavelength, and anything over that will disinfect? I believe the FormCure is somewhere in the 405nm range…
Hope everyone is staying safe. Me and little CurlyBee are hunkered down.
As sunlight passes through the atmosphere, all UVC and approximately 90% of UVB radiation is absorbed by ozone, water vapour, oxygen and carbon dioxide. UVA radiation is less affected by the atmosphere. Therefore, the UV radiation reaching the Earth’s surface is largely composed of UVA with a small UVB component.
The shorter-wavelength, higher-energy UV radiation associated with the UVC category is very strongly absorbed by most organic materials. This is why the common 254 nm sources have become so popular for germicidal/disinfectant applications. The strong absorption by organic molecules, including DNA, leads to severe damage to the molecule and to the organism’s reproductive processes, leading to the death of the microbes.
The UVC radiation is sufficiently energetic that individual photons may produce chemical bond breakage and ionization of some atoms and molecules. The preferential absorption of particular energy photons by materials, both organic and inorganic, is evident throughout the electromagnetic spectrum from microwaves through infrared and visible light, ultraviolet, x rays, and gamma rays. The absorption at particular wavelengths may be associated with resonance-type effects in which the gaps between certain energy states in an atom or molecule are nearly matched by the energies of the incoming photons. Atomic or molecular excitation may occur as a result of the absorption, or an electron may be ejected from an atom when the incoming photon energy exceeds the binding energy of the electron in the atom. It is common that photon absorption by particular atoms or molecules may be small at a given energy, increase with increasing energy, and then decrease again at yet higher energies, so it is not surprising that some higher-energy UV radiation may be more strongly absorbed than lower-energy UV.
To use UV to destroy bacteria and virus efficiently it needs to be in the UVC range, which is dangerous to humans, it attacks skin (burns and possibly skin cancer) and subject to the power of the source can destroy eye sight in seconds. At best even lower power UVC causes serious eye irritation, dependent on the power and length of exposure your eyes MIGHT recover (or you may go blind…
Thank you so much for this…my mom was a science teacher but she passed several years ago. I grew up with a love of science. This makes perfect sense…I appreciate the time you took to respond.
I also realized that a wren abandoned some eggs in a nest in my outdoor kitchen…I’ve currently got them under an incandescent light bulb in my closet, but I wondered about using the FormCure for that as well. I don’t think they’ll hatch, but I’ll give it a shot with the incandescent light. I was thinking about 3D printing an egg turner since Amazon can’t deliver an incubator until three weeks from now.