Quantitative UV-C dose validation with photochromic indicators for informed N95 emergency decontamination
Abstract
With COVID-19 N95 shortages, frontline medical personnel are forced to reuse this disposable–but sophisticated–multilayer respirator. Widely used to decontaminate nonporous surfaces, UV-C light has demonstrated germicidal efficacy on porous, non-planar N95 respirators when all surfaces receive ≥1.0 J/cm2 dose. Of utmost importance across disciplines, translation of empirical evidence to implementation relies upon UV-C measurements frequently confounded by radiometer complexities. To enable rigorous on-respirator measurements, we introduce a photochromic indicator dose quantification technique for: (1) UV-C treatment design and (2) in-process UV-C dose validation. While addressing outstanding indicator limitations of qualitative readout and insufficient dynamic range, our methodology establishes that color-changing dosimetry can achieve the necessary accuracy (>90%), uncertainty (95%) required for UV-C dose measurements. In a measurement infeasible with radiometers, we observe a striking ~20× dose variation over N95s within one decontamination system. Furthermore, we adapt consumer electronics for accessible quantitative readout and use optical attenuators to extend indicator dynamic range >10× to quantify doses relevant for N95 decontamination. By transforming photochromic indicators into quantitative dosimeters, we illuminate critical considerations for both photochromic indicators themselves and UV-C decontamination processes.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 06, 2021
- Source ID
- 10.1371/journal.pone.0243554
Entities
People
- Alisha Geldert
- Alison Su
- Amy E Herr
- Anjali Gopal
- Samantha M. Grist
Organizations
- Chan Zuckerberg Biohub
- National Institutes of Health
- National Science Foundation
- Natural Sciences and Engineering Research Council