UVGI is fairly straight forward and well documented, but being effective on fabric masks takes more planning and horsepower than doing it on hard surfaces.

Note: UVGI is performed using bulbs that emit UV-C radiation that are labeled as having a specific germicidal/disinfection purpose. These are not standard grow lights. For an example, here is a manufacturer’s page showing specifications for an appropriate bulb.

We have found the following documents to be good summaries of UVGI treatment on N95 masks:

Applied Research Associated released this report in 2019 that provides a helpful executive summary of UVGI as a strategy for addressing shortages of PPE during a public health emergency.

The CDC posted an informative overview of different methods of treating N95’s on April 9 here. Two of the primary sources they cite in this report are the 2019 ARA report just above (lead author Brian Heimbuch), and the 2015 Lindsley et. al. paper at the top of the bibliography below.

The University of Nebraska Medical Center released this report on their use of UVGI to treat PPE during the Covid-19 pandemic. Note their design is different design than ours, but it is a good overview and includes their protocol.

UMass Memorial Hospital is using UVGI in the Covid-19 pandemic.

Colorado’s South Fork Fire Department has posted their UVGI design. It is smaller than ours, but the concept is the same.

Bibliography

An April 16, 2020, New York Times science blog titled, “Disposable N95 Masks Can Be Decontaminated, Researchers Confirm,” summarized several methods to sanitize PPE, including UVGI.

Lindsley, WG, SB Martin, Jr., RE Thewlis, K Sarkisian, JO Nwoko, KR Mead and JD Noti (2015). Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity. J Occup Environ Hyg 12(8): 509-17.
https://www.ncbi.nlm.nih.gov/pubmed/25806411

Heimbuch, BK, WH Wallace, K Kinney, AE Lumley, CY Wu, MH Woo and JD Wander (2011). A pandemic influenza preparedness study: use of energetic methods to decontaminate filtering facepiece respirators contaminated with H1N1 aerosols and droplets. Am J Infect Control 39(1): e1-9. https://www.ncbi.nlm.nih.gov/pubmed/21145624

Fisher, EM and RE Shaffer (2011). A method to determine the available UV-C dose for the decontamination of filtering facepiece respirators. J Appl Microbiol 110(1): 287-95.
https://www.ncbi.nlm.nih.gov/pubmed/21054699

Lore, MB, BK Heimbuch, TL Brown, JD Wander and SH Hinrichs (2012). Effectiveness of three decontamination treatments against influenza virus applied to filtering facepiece respirators. Ann Occup Hyg 56(1): 92-101. https://www.ncbi.nlm.nih.gov/pubmed/21859950

Woo, MH, A Grippin, D Anwar, T Smith, CY Wu and JD Wander (2012). Effects of relative humidity and spraying medium on UV decontamination of filters loaded with viral aerosols. Appl Environ Microbiol 78(16): 5781-7. https://www.ncbi.nlm.nih.gov/pubmed/22685135

Mills, D, DA Harnish, C Lawrence, M Sandoval-Powers and BK Heimbuch (2018). Ultraviolet germicidal irradiation of influenza-contaminated N95 filtering facepiece respirators. Am J Infect Control 46(7): e49-e55. https://www.ncbi.nlm.nih.gov/pubmed/29678452

Viscusi, DJ, MS Bergman, DA Novak, KA Faulkner, A Palmiero, J Powell and RE Shaffer (2011). Impact of three biological decontamination methods on filtering facepiece respirator fit, odor, comfort, and donning ease. J Occup Environ Hyg 8(7): 426-36.
https://www.ncbi.nlm.nih.gov/pubmed/21732856

Heimbuch, BK, K Kinney, AE Lumley, DA Harnish, M Bergman and JD Wander (2014). Cleaning of filtering facepiece respirators contaminated with mucin and Staphylococcus aureus. Am J Infect Control 42(3): 265-70. https://www.ncbi.nlm.nih.gov/pubmed/24462175

Viscusi, DJ, WP King and RE Shaffer (2007). Effect of Decontamination on the Filtration Efficiency of Two Filtering Facepiece Respirator Models. J Int Soc Respir Prot 24: 93-107.

Viscusi, DJ, MS Bergman, BC Eimer and RE Shaffer (2009). Evaluation of five decontamination methods for filtering facepiece respirators. Ann Occup Hyg 53(8): 815-27. https://www.ncbi.nlm.nih.gov/pubmed/19805391

Vo, E, S Rengasamy and R Shaffer (2009). Development of a test system to evaluate procedures for decontamination of respirators containing viral droplets. Appl Environ Microbiol 75(23): 7303-9. https://www.ncbi.nlm.nih.gov/pubmed/19801477

Bergman, MS, DJ Viscusi, BK Heimbuch, JD Wander, AR Sambol and RE Shaffer (2010). Evaluation of multiple (3-cycle) decontamination processing for filtering facepiece respirators. J Eng Fibers Fabrics 5(4): 33-41. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1089&context=usafresearch

Fisher, EM, J Williams and RE Shaffer (2010). The Effect of Soil Accumulation on Multiple Decontamination Processing of N95 Filtering Facepiece Respirator Coupons Using Physical Methods. J Int Soc Respir Prot 27(1): 16-26.

Salter, WB, K Kinney, WH Wallace, AE Lumley, BK Heimbuch and JD Wander (2010). Analysis of residual chemicals on filtering facepiece respirators after decontamination. J Occup Environ Hyg 7(8): 437-45. https://www.ncbi.nlm.nih.gov/pubmed/20526947

Woo, M-H, Y-M Hsu, C-Y Wu, B Heimbuch and J Wander (2010). Method for contamination of filtering facepiece respirators by deposition of MS2 viral aerosols. J Aerosol Sci 41(10): 944-952.
http://dx.doi.org/10.1016/j.jaerosci.2010.07.003

Bergman, MS, DJ Viscusi, AJ Palmiero, JB Powell and RE Shaffer (2011). Impact of Three Cycles of Decontamination Treatments on Filtering Facepiece Respirator Fit. J Int Soc Respir Prot 28(1): 48-59.

Fisher, EM, JL Williams and RE Shaffer (2011). Evaluation of microwave steam bags for the decontamination of filtering facepiece respirators. PLoS ONE 6(4): e18585.
https://www.ncbi.nlm.nih.gov/pubmed/21525995

Lin, TH, CC Chen, SH Huang, CW Kuo, CY Lai and WY Lin (2017). Filter quality of electret masks in filtering 14.6-594 nm aerosol particles: Effects of five decontamination methods. PLoS ONE 12(10): e0186217. https://www.ncbi.nlm.nih.gov/pubmed/29023492

Lin, TH, FC Tang, PC Hung, ZC Hua and CY Lai (2018). Relative survival of Bacillus subtilis spores loaded on filtering facepiece respirators after five decontamination methods. Indoor Air 28(5): 754-762. https://www.ncbi.nlm.nih.gov/pubmed/29855107