Yes, but they do often differ from the protocols and equipment used to validate 254nm or 265nm UV-C performance. Below are a couple of the challenges we have encountered in the market and solutions for them:
254nm calibrated dosage strips or dosimeters often do not accurately measure 222nm fluence/dosage. While many of these devices claim detection capabilities for wavelengths between 200-280nm, they are often one or more orders of magnitude less likely to detect light at the portion of the spectrum they were intended to target and/or extrapolate expected dosage. Far UV Technologies primarily uses and recommends NIST calibrated Gigahertz and International Light Technologies sensors for accurate UV-C measurements in the labs and in the field. These are commercially available for purchase, although somewhat expensive if you are not regularly collecting data. Far UV Technologies and/or its installers provide NALMCO certified installations with as-installed dosage confirmation when we or our network of contractors install in-room UV solutions. In addition, other industry participants such as Columbia University have created new 222nm calibrated films that can also indicate actual dosage in application.
Measuring microbiological efficacy in the field is often not particularly fast or accurate for any pathogen reduction solution as the preexisting bacterial or viral loads and types are typically unknown in the real world. The current gold standard for pathogen reduction efficacy is to introduce known concentrations of known pathogens, treat them, culture them and then determine pathogen reduction efficacy ~24-48 hours later. However, few end users prefer to introduce virulent pathogens into their environments due to the intrinsic safety risks. As a result, accurately measuring the UV fluence as noted above and then referencing tables of lab proven efficacy are often the best ways to validate and certify expected pathogen reduction safely in facilities and vehicles. That said, Far UV Technologies is supporting several academic and industry studies and will continue to welcome and support institutional partners to further validate our products in the field and in the labs.
PCR techniques can help identify bacterial or viral presence but are not good at confirming whether RNA is alive (viable) or dead, just that it is present. This is particularly challenging with 222nm as Far UV inactivates or kills the pathogens through protein damage, eliminating the chance of infectivity but the nonviable cells are still detected with PCR. We confirmed this under our NASA testing and Hiroshima University confirmed it as well in their published study on 222nm efficacy against SARS-CoV-2 It is now considered common knowledge and best practice to use the TCID50 assay, which has proven to be a more accurate microbiological test method than PCR to determine pathogen viability.
Some standardized test protocols utilize protein-rich bovine or other solutions when testing which inhibit 222nm test accuracy. A growing body of evidence is suggesting the most dangerous particles are the smallest droplets that can remain airborne longer and can reach deeper into the lungs of an uninfected individual. The smaller the droplet, the less potential saliva or other accompanying materials/solution and the less the real-world impact on 222nm penetration of the targeted pathogens. Ironically, the efficacy of 222nm Krypton Far UV in saliva has been shown to be even more effective as the natural decay is reduced in the controls, but the inactivation of Far UV has not been materially impacted.
We recommend end users utilize NALMCO certified GUV installers. Far UV Technologies and AeroMed are certified GUV Management Consultants, the highest level of certification ensuring safe and effective installations.
