Ultraviolet Germicidal Irradiation on the New Silicone Half-Piece Elastometric Respirators

We used the Porcine epidemic diarrhea virus (PEDV) as the indicator virus .An N99 mask was contaminated by spraying or applying with the virus on the exterior and interior surface of each silicone mask. Also, 100 μl of the viral suspension was spotted onto the filter part of N99 masks. Following 20-30 minutes of drying, the silicone masks underwent each of the decontamination procedures which are ultraviolet-C (UV-C) irradiation and 70% alcohol treatment. For UV irradiation, N99 masks were placed in an UV-C incubator ) and were exposed for different times at 1, 10 and 20 minutes, respectively.Untreated control and treated N99 masks were analyzed for viral infectivity in VERO cell cultures. At 48 hours post-infection, cells were examined for evaluation the viral infectivity via observation of cytopathic effect. Results for each treatment express mean ± standard deviations of 3 biological replicates.

Bacterial and fungal sampling were obtained from the inside and outside surface areas likely to the frequently touched and close contact with the face of hospital personnel. The cultures were then isolated onto the blood agars and Mac Conkey agars, respectively. After incubation, the total number of bacterial and fungal colonies were counted, recorded, and selected different colonies.

All the participants had to pass the initial fit test.After decontamination with UVC irradiation for 60 minutes, fit testing was conducted using qualitative fit test (Bittrex Solution aerosol),

We measured the tensile strength of the strap of the Silicone mask before and after the UVC irradiation to study the strength and reliliency of the strap