How Safe is Ultraviolet-C (UV-C)?
UV-C has been proven useful in the fight against numerous bacteria, viruses, and mold. But how safe is it?
As the world comes to terms with the first great global pandemic in recent times, technology like UV-C disinfection lighting will play an ever more important part in our keeping us safe now, and into the future.
At UVClean, we've talked about UV-C in our blog and social media in recent months and we’ve received one question more than any other: is it safe? So, in response, here’s a quick breakdown of how UV-C works and how it can be used in an effective and safer way to keep our shared spaces disinfected and hygienic.
How UV-C Disinfection Works
UV-C Is Naturally Produced By The Sun!
We don’t come into contact with UV-C because it is filtered out by the ozone layer in the Earth’s atmosphere. The wavelength of UV-C light is shorter than the wavelength of the light we can see and spans the range of 100-280 nanometers (nm). It is most effective at inactivating viruses on or around 260-265nm, known as the ‘germicidal peak.’ UVClean's UV-C lamps operate at 254nm, which is proven to be highly effective in inactivating viruses, bacteria and mold spores.
Humans and animals should not be exposed to germicidal UV-C light at this wavelength as it can cause damage to their skin and eyes in a matter of minutes1 of exposure. Proper protective equipment and must be used when operating germicidal UV-C products. That said, provided that our UV-C products are used and installed correctly and in accordance with our user manuals and mounting instructions, UV-C is a reliable and highly effective form of disinfection, with safety risks mitigated by the appropriate safeguards put in place.
UV-C’s Effectiveness Disinfectant
"All micro-organisms that have been tested so far for UV-C exposure were shown not to be resistant to
UV-C is very effective, and has even been proven effective in inactivating the airborne virus responsible for the global pandemic³. All micro-organisms that have been tested so far for UV-C exposure were shown not to be resistant to UV-C light. Additionally, Boston University recently tested germicidal UV-C light sources on the virus responsible for the global pandemic. The team applied a dose of 5mJ/cm2, resulting in a reduction in the virus of 99% in 6 seconds. Based on the data, it was determined that a dose of 22mJ/cm2 will result in a reduction of 99.9999% in 25 seconds.⁴
To further eliminate the risk of infection, UV-C can be used in combination with other disinfection methods like traditional scrubbing using chemical disinfectant. In high contact areas such as a gym, restroom or hospital treatment room, such additional safeguards ensure that areas that are shaded from the reach of the UV-C light are also disinfected.
"There are instances where UV-C can be applied where other methods of disinfection can’t”
1 Timing depends on the power of the UV-C source and proximity of the person to it. For most applications it is 1-2 minutes, although it can be shorter.
2 Other than medical devices.
3 Buonanno, M., Welch, D., Shuryak, I. et al. Far-UVC light (222 nm) efficiently and safely inactivates airborne human viruses. Sci Rep 10, 10285 (2020).
⁴ The time it takes to disinfect depends on the power of the UV-C source and proximity. Disinfection times vary with these parameters.