Source avec lien : American Journal of Infection Control, 50(8). 10.1016/j.ajic.2022.03.003
Un panel de masques respiratoires N95, de masques médicaux et de masques en tissu a été pulvérisé avec 5 cycles de solution de bleu de méthylène 1 000 uM. Les coupons de masques ont été soumis à l’équivalent de 120 L/min d’un débit d’air humidifié à 100 %. Le gaz effluent a été piégé dans une solution aqueuse et le fluide résultant a été échantillonné pour l’absorption de bleu de méthylène avec un niveau de détection de 0,004 mg/m3.
Background Global shortage of personal protective equipment (PPE), as consequence of the COVID-19 global pandemic, has unmasked significant resource inequities prompting efforts to develop methods for safe PPE decontamination for reuse. The World Health Organization (WHO) in their Rational Use of PPE bulletin cited the use of a photodynamic dye, methylene blue, and light exposure as a viable option for N95 respirator decontamination. Because WHO noted that methylene blue (MB) would be applied to surfaces through which health care workers breathe, we hypothesized that little to no MB will be detectable by spectroscopy when the PPE is subjected to MB at supraphysiologic airflow rates. Methods A panel of N95 respirators, medical masks, and cloth masks were sprayed with 5 cycles of 1,000 uM MB solution. Mask coupons were subjected to the equivalent of 120 L/min of 100% humidified air flow. Effluent gas was trapped in an aqueous solution and the resultant fluid was sampled for MB absorbance with a level of detection of 0.004 mg/m3. Results No detectable MB was identified for any mask using Ultraviolet-Visible spectroscopy. Conclusions At 500-fold the amount of MB applied to N95 respirators and medical masks as were used for the decontamination study cited in the WHO Rational Use of PPE bulletin, no detectable MB was observed, thus providing safety evidence for the use of methylene blue and light exposure for mask decontamination.