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Health Sciences


LC Yang

Mentor Department

Health Sciences


The purpose of this research is to test the filtering efficiency of N95 respirators when recharged using an electrostatic charging device invented by the F.N. Smith corporation. If charging is found to be successful, potential opportunity lies within increasing protection, efficiency, and reuse of N95 respirators. All 20 unused respirators were fitted to a mask holder made of PVC pipe with two tubes, one for the vacuum pump set at 10 LPM and the other to measure the background particle concentration, using a particle counter. Each mask was tested once for filtration before being charged, with frequent background concentration checked every 30 minutes to ensure accurate readings. Recharging of the new respirators was done for five minutes then the filtration was tested again. The N95 respirators were decontaminated by two methods, cooking and UV irradiation, then recharged for an additional five minutes post cleaning. Test filtration was done again using the same experimental procedure noted at the start. The largest obstacle faced was creating an environment to mimic ideal conditions for proper N95 respirator use and filtration. This issue was resolved by using outdoor air from above a street, which when tested had substantially more particles than the air inside the lab. The results showed us information regarding the efficiency of new respirators and post- decontaminated respirators. Data analysis showed that the efficiency of the new mask without recharge was 93.1% for 0.3 micrometer particles. After the five-minute recharging, the efficiency was increased to 97%. the filtration efficiency didn’t decrease after going through the reuse- decontamination-recharging cycle twice, but slightly decreased after the third time.

Test The Filtration Efficiency Of N95 Respirators Recovered Using An Electrostatic Charging Device