During the COVID-19 pandemic, usage of face masks has become essential as they provide a basic barrier against harmful particulates. In particular N95 masks work as a first line of defense that is widely used among all health care providers. These NIOSH approved N95 respirators are a special part of Personal Protective Equipment (PPE). It can reduce the risk of getting harmful airborne particles which can cause coronavirus or other respiratory infections.
N95 respirators which are NIOSH approved and regulated by FDA and CDC have some qualities that make it become the top priority during the pandemic. N95 respirators can block the pathogen that comes out when an infected person is coughing, sneezing, talking, or breathing. It has a 95% filtration efficiency. It can filter out as small as 0.3 microns non-oil resistant particles. N95 respirators are made for one-time use only. It is of no benefit to reuse N95 respirator because by every time you take it off it reduces the efficiency of filtering 95% of hazardous particles.
N95 respirators for its high efficiency and filtering ability are specially made for the use of doctors, nurses, paramedical staff, and workers because they are directly in contact with the coronavirus patients hence are at high risk of getting infected. As the news breaks for the rapid increase in the number of coronavirus infected patients. All people around the world start purchasing NIOSH-approved N95 respirators that are meant to be used only in the health care setting.
The demand for N95 respirators in all health practitioners was also rapidly increasing due to the increasing number of coronavirus infected people. The rapid increase in the N95 respirator’s demand results in its short supply. Many experts also say that the short supply will never happen if N95 respirators can be reused so that one person could utilize only one mask during its working hours.
Techniques to Reuse N95 Respirators
Due to the shortage in N95 respirators supply different countries use different strategies to overcome this scarcity. Most of the country’s experts suggested a contamination method so that N95 respirators can be reused and will continue the supply to the hospitals where it is much needed.
The problem gets worse because many healthcare workers decontaminate masks by procedures using UV lights, dry and wet heat, hydrogen peroxide method, boiling methods, baking, and fumigation methods. This was soon declared that these methods were of no use because they can badly affect the filtration efficiency of the N95 respirator. Soon after experts start working on restoring the filtration efficiency of N95 respirators so that it can be reused. The conclusion made, even after decontamination from the various methods, the mask can still be used for its 95% efficiency and it can either be done mechanically or electrostatically.
Restore Efficiency of N95 mask by using Electricity
After decontamination N95 respirators have lost their efficiency of filtering 95% airborne particles, after that these masks will be of no use. Experts claim that they can restore the efficiency of the N95 respirator the same as the brand new one. For this method they used a powered battery mask without the filter for maintaining a high filtration level after several hours of charging.
To test the result of their claim, experts first measured the filtration efficiency of different companies N95 respirators (all were ranges from 95% to 98% as expected). Then they use different decontamination methods starting with sanitizing all N95 respirators with ethanol or by passing them through hot water or by using the steam method or just by throwing all of them in the washing machine. After every decontamination method, the filtration efficiency of every N95 respirator decreases as expected.
For restoring the filtration efficiency of the N95 respirator, all masks were placed between two metal electrodes containing the electric field of 800 volts per millimeters. The electric field should be high enough so that the polypropylene fabric of the N95 respirator can conduct the electric charge and stored all charges in the fabric to regain its filtration efficiency. Some researchers also suggest using a high voltage hair dryer to store the charge by the N95 polypropylene fabric. After about an hour of charging the experts stop the electricity conduction and leave all N95 respirators for a while so that the charge can fully store in the polypropylene fabric. When the team tested the filtrating ability of recharged N95 respirators, they were surprised to get back 95% filtration ability of decontaminated N95 respirators as they were in a brand new packet and this filtration method allows N95 masks to be used for longer time duration having efficient filtration of 95%. The results were satisfying but the question arises about the process of filtration testing.
The inventor of N95 respirator Peter Tsai said after this testing that we cannot rely on any rough commercial apparatus to test the filtration efficiency of N95 respirators as it is meant to be used in health care setups, it should be properly tested and verified. For the satisfaction of the testing method, Levis who conducted this experiment said that we tested the filtration efficiency after decontamination of N95 respirators on standard methods.
After getting the expected results from this experiment, Levis also came up with an idea to make a smart respirator that can be charged through smartphones with the required current amount after decontamination. These methods can be considered as a quick and smart solution in the period of the N95 respirator shortage.