The resistances of respirators were mostly consistent regardless of treatments, except that laundering treatments slightly decreased the resistance of Resp. A. The physical characteristics of respirators before and after treatment were further investigated in later sections. As for the filtration efficiency, the organic solvents such as IPA and EtOH, and detergent-laundering deteriorated the filtration efficiency of both respirators. Particularly for IPA and EtOH treatments, up to ~28% of efficiency was lost after treatments. Considering that the resistance of the solvent-treated samples was unchanged, it can be inferred that the solvents caused the reduction of filtration performance by affecting the electrostatic filtration capacity, rather than disrupting the structural integrity. Similarly, the filtration efficiency was notably reduced after laundering with detergent. As laundering with water barely affected the filtration efficiency, this indicates that the detergent negatively affected it, probably through an impact on the electrostatic capture mechanism.