Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity

The ability to disinfect and reuse disposable N95 filtering facepiece respirators (FFRs) may be needed during a pandemic of an infectious respiratory disease such as influenza. Ultraviolet germicidal irradiation (UVGI) is one possible method for respirator disinfection. However, UV radiation degrades polymers, which presents the possibility that UVGI exposure could degrade the ability of a disposable respirator to protect the worker. To study this, we exposed both sides of material coupons and respirator straps from four models of N95 FFRs to UVGI doses from 120–950 J/cm2. We then tested the particle penetration, flow resistance, and bursting strengths of the individual respirator coupon layers, and the breaking strength of the respirator straps. We found that UVGI exposure led to a small increase in particle penetration (up to 1.25%) and had little effect on the flow resistance. UVGI exposure had a more pronounced effect on the strengths of the respirator materials. At the higher UVGI doses, the strength of the layers of respirator material was substantially reduced (in some cases, by >90%). The changes in the strengths of the respirator materials varied considerably among the different models of respirators. UVGI had less of an effect on the respirator straps; a dose of 2360 J/cm2 reduced the breaking strength of the straps by 20–51%. Our results suggest that UVGI could be used to effectively disinfect disposable respirators for reuse, but the maximum number of disinfection cycles will be limited by the respirator model and the UVGI dose required to inactivate the pathogen.

在流感等传染性呼吸道疾病大流行期间，可能需要具备对一次性N95过滤式面罩呼吸器（FFR）进行消毒和重复使用的功能。紫外线杀菌辐照（UVGI）是呼吸器消毒的一种可能方法。然而，紫外线辐射会降解聚合物，这可能导致UVGI暴露降低一次性呼吸器保护工人的能力。为此，我们分别将四款N95 FFR的材质样品和呼吸器带的两面暴露于120至950 J/cm²的UVGI剂量下。随后，我们对单个呼吸器样品层进行了颗粒穿透率、气流阻力和爆破强度的测试，并对呼吸器带的断裂强度进行了测试。我们发现，UVGI暴露导致颗粒穿透率小幅上升（最高达1.25%），对气流阻力影响甚微。UVGI暴露对呼吸器材料的强度影响更为显著。在较高UVGI剂量下，呼吸器材料层的强度显著降低（某些情况下，降低幅度超过90%）。不同型号呼吸器材料强度变化差异较大。UVGI对呼吸器带的影响较小；2360 J/cm²的剂量将带子断裂强度降低了20至51%。我们的结果表明，UVGI可以有效地用于消毒一次性呼吸器以供重复使用，但最大消毒次数将受呼吸器型号及灭活病原体所需UVGI剂量所限。