Safely Masking On A Tight Budget
Updated: Jul 31, 2020
At even a dollar per disposable mask the costs accumulate and can break the
piggy bank for someone trying to get by on a reduced income from COVID-19. There is scientific evidence that you can reduce the risk of reusing a contaminated mask by taking a few simple precautions.
The New England Journal of Medicine released a paper on the lifestyle of SARS-COV-2, that examined the lifespan of the virus on common surfaces. The data showed that the virus is more stable on plastic and stainless steel than on copper and cardboard. Viable virus was detected for a maximum period of 72 hours after application to these surfaces. Therefore, it is highly unlikely that a mask that has trapped virus on its outer surface will still retain infectious virus if you simply hang the mask in a clean room where the outer surface is constantly exposed to direct sunlight for 96 hours (four days).
With radioactive material the half-life is the interval of time required for one half of the atomic nuclei of a radioactive sample to decay. Viruses follow along the same lines. Viruses similarly become enviable (essentially dead) over time when they remain outside of a host that provide them with a stable environment for their survival. There are a number of factors that determine the half-life of a specific virus, including the physical and bio chemical properties of the virus itself and the particular set of environmental factors surrounding the virus. Without getting too nerdy with detail, as an example, an enveloped RNA virus, (like SARS-COV-2) reacts differently compared to a virus that does not have an envelope (Which is certain kind of protective shell). This is because the envelope itself protects the virus interior and it has a specific set of chemical properties that respond to sunlight, temperature, air and other things.
A few years ago before we bought our latest home my wife and I stayed in an
apartment. If someone were to take samples it is very likely that they would find
my DNA in the apartment, despite my best efforts to clean before we moved out.
However, the DNA found obviously does not mean that I am still alive in that apartment.
Taking this idea just a little bit further, let’s say the same DNA samples were taken
while we were still living in the apartment. You might expect those samples to
reveal a much higher DNA count. You would be correct.
Similarly, the samples of virus particles were collected for the study above measured viral RNA, a nucleic acid similar to DNA. Above a certain threshold viral RNA is known to be infectious. But a few pieces of RNA that have been around for a while are not a danger because they can safely be presumed enviable. In the actual study, the lab technicians take the viral particles found and put them in a plate of Vero cells, (kidney cells) add the proper nutrients and incubate them at just the right temperature to provide for viral replication. If the
cells do not replicate it means that they are no longer viable. This is how they
know that 72 hours is the longest duration the virus can survive on the four
surfaces that they tested.
There is no way to lower the risk of reusing a disposable mask to zero. It is possible to infect one’s self simply by failing to follow the correct procedure for doffing the mask, and or improperly handling the mask after one takes it off. The safest thing to do is to wear a fresh mask each time you go out and to carefully discard the mask in a contained trash receptacle after use. That is what the CDC recommends. If you do choose to reuse, think through every step in your donning and doffing. (Putting on the mask and taking it off. Including handling it, (using hand sanitizer and or washing your hands with soap and water) after touching and or a setting soiled mask on a pre-sanitized table. It makes sense to sanitize cloths pins and so on. Too much precaution beats too little every time.
Do all of that, plus maintain physical distance between yourself and others and you substantially increase your chances of remaining healthy. Do not be the one refusing to wear masks in public by rationalizing the financial hardship. Ultimately, the risk you assume is your own responsibility. I offer this information, not as medical advice but simply as a survey of the science for educational purposes so that you can make a better informed decision about this important public health matter. If you can't wear a mask for medical reasons, please just stay at home and be social using zoom.