With the Covid-19 pandemic now dragging on well into its second year, it has become increasingly clear that we will have to find long-term ways to adapt to and deal with the virus. For better or worse, this crisis has created an unprecedented interest in what, exactly, is lingering in our indoor air. Researchers around the world had been studying this critical public health issue even before Covid-19 emerged, but the ongoing pandemic has only increased the urgency of understanding and tackling this problem.
Molekule has also been studying how air purification can help address the problems posed by the Covid-19 virus. More specifically, our research has been focused on capturing proxy viruses and inert virus-sized particles. In 2020, we partnered with the University of Minnesota for a project that looked into how effective PECO technology and Air Mini are at deactivating influenza and animal strains of coronaviruses in the air.
This year, PECO is the subject of experiments conducted at the University of Nebraska Medical Center where experts performed additional experiments on a strain of SARS-CoV-2 (the virus responsible for the global Covid-19 pandemic) that was originally discovered in an infected person in Wisconsin.
The results were promising: Data showed that Air Mini was able to remove 99.98% of the virus from the air in a small chamber in a relatively short time. We also found that the PECO-Filter added another layer of protection with its ability to destroy organic matter, rendering 99.42% of viruses applied directly to the filter incapable of infection.
Here is how we conducted the experiments:
Test number one: Destruction of the virus particles
The virus that causes Covid-19, SARS-CoV-2, exists as a virus particle that can float through the air. The particle consists of little more than a protein shell called a capsid that it uses to invade a host cell, and genetic material that replicates more capsid proteins. The capsid is covered by spike proteins, which are the targets of the Covid vaccines. If all the spike proteins are blocked or suffer even minor damage, then the virus cannot infect.
The Covid diagnostic tests that have been administered since early 2020 are primarily PCR tests, which look for genetic material. For this test, however, we also wanted to look for virus particles that could have intact genetic material but that could not infect as a result of exposure to PECO.
To do this, the team first placed the virus directly onto PECO-filter swatches and also onto identical filter swatches without PECO as a control. The swatches were allowed to sit for a set amount of time to allow the catalyst to begin destroying the virus particles. The swatches were then extracted and tested for the presence of viable viruses.
To test how well the virus did or did not survive, the team used a standard but complex procedure that involves infecting a cultured cell line with the extracted virus from the filter. The exposed cells are then soaked with a stain that makes SARS-CoV-2 glow bright green if it has infected a cell. These images below show the difference in infected cells :
The left column of images are cells infected by viruses that have not been exposed to PECO, the center column shows cells infected by viruses that have been exposed to PECO, and the single picture in the upper right shows cells that have never been infected by viruses. You can see that the samples from one hour and four hours of PECO exposure look very much like the cells that have never been infected. This shows how quickly a virus exposed to PECO can be rendered non-viable.
Investigating the integrity of the spike proteins in the capsid was well beyond the scope of this research, but the oxidative power of PECO had a clear and drastic impact on how well the virus can infect. By the first measurement after one hour, there were practically no infectious viruses discovered. The team also used extremely accurate lab equipment to measure the degree of green in the infected cultures, and measured a destruction rate of 99.42% in under an hour, as shown in the graph below.
Test number two: Virus capture
Research on SARS-CoV-2 requires what is known as Biosafety Level 3 precautions. These stringent requirements are in place to minimize the possibility of an infection as a result of the research. The technicians must wear full PPE with a face mask and perform all experiments in a specially designed, negative-pressure environment.
How viruses are released into the air for study and under what conditions are tightly controlled in Biosafety Level 3 facilities, so sensitive experiments are performed in a 5.3 cubic-foot cabinet that can be easily cleaned and purged. Following these protocols, the researchers placed Air Mini into this secure space before aerosolizing the virus. Air Mini was activated on Speed 1 (its lowest speed setting) while the air was sampled over time and analyzed for virus reduction. The results are in the graph below.
These measurements show that by the first measurement a little after two minutes, the concentration of airborne viruses dropped below the detection limit, even with Air Mini running on its slowest speed. This is consistent with other virus capture experiments we have done that are available here, so at the very least this tells us that SARS-CoV-2 is not a special case and is captured much in the same way as other viruses. The measured rate for this experiment was 99.98% capture.
Conclusion: PECO helps remove and destroy SARS-CoV-2
These two experiments show how PECO works together with traditional filtration to provide a multi-layered approach to airborne viruses. Not only do Molekule’s high efficiency filters physically remove them, but PECO goes one step further to make them less capable of infecting. Given that exposure to a higher viral load can lead to a more severe infection, any reduction in infectious particles is a welcome result. No air purifier can prevent transmission of a virus, however. Molekule recommends use of PPE and following directions of the CDC and other government authorities.