Quantification of photochromic indicators for UV-C dose validation of N95 respirator decontamination

COVID-19-induced personal protective equipment shortages necessitate effective, accessible N95 decontamination, especially in low-resource settings. UV-C irradiation inactivates SARS-CoV-2 analogs on N95 respirators when ≥1.0 J/cm^2 is delivered[1]. However, lack of robust and scalable UV-C dose validation tools impedes effective, widespread adoption. Tailored for field-deployment in settings lacking specialized UV-C radiometers, we design workflows to quantify photochromic UV-C dose indicators and extend dynamic range using low-cost filters. We demonstrate that photochromic quantification meets specifications required for robust UV-C measurements. Previously infeasible on-N95 measurements show ~20X dose variation within a UV-C system, highlighting how photochromics can underpin new validation strategies. Reference: 1. Brian Heimbuch and Del Harnish. Research to Mitigate a Shortage of Respiratory Protection Devices During Public Health Emergencies. (2019).