Using an air purifier to combat airborne germs

With the ever-present threat of the COVID-19 virus looming, the subject of using air purifiers to combat airborne germs has garnered great attention within the past three years. You may have heard that employing air purifiers in your home or office may help combat this threat, but what does the science say? Do air purifiers help protect us from airborne pathogens? Below we will discuss how an air purifier can protect you from dangerous pathogens present in your breathing air.

Transmission of airborne pathogens

First, it helps to understand how airborne pathogens and germs are transmitted. When a person breathes, sneezes, or coughs, small aerosol particles are released into the air around them. These tiny droplets are then suspended in the air where they can stay for up to one hour, even more according to some studies¹. Viruses, germs, and/or pathogens can all be found inside these aerosol particles if that person is infected, and if another person enters the room within one hour’s time, that person is then left exposed to the same viruses, germs, and/or pathogens. This is exactly how the COVID-19 virus was able to proliferate so rapidly and efficiently, ultimately leading to 600 million confirmed cases and 6.5 million deaths worldwide (according to WHO figures, as of 7 November 2022). 

How do air purifiers work?

How an air purifier works is that it pulls in air from your interior space, trapping particles suspended in the air that can be harmful to your health like pollen, dust, and bacteria. The same goes for trapping aerosol particles suspended in the air, and the air purifier then does what it does best by filtering out the aerosol particles that contain viruses or pathogens. Some air purifiers, such as Eoleaf’s, come equipped with UV sterilisation technology which is the most effective method of destroying viruses and pathogens such as the flu virus and, yes, the COVID-19 virus. To read more about the specific filtration layers in Eoleaf’s air purifiers, take a look here.

Does this mean you can go out and buy any old air purifier in the hopes that it’ll protect you from airborne pathogens? Not quite! Not all air purifiers are created equal. It is important to find an air purifier that contains a HEPA (high-efficiency particulate air) filter. The gold standard of air filtration, any filter capable of filtering at least 99.97% of particles of a size greater than or equal to a diameter of 0.3 µm in a single pass receives this designation. It is a term defined by European standards EN 1822 and EN ISO 29463 in 2009. All Eoleaf air purification products contain HEPA filters.

The 0.3 µm myth

You may have seen articles claiming that HEPA filters are ineffective against the COVID-19 virus which has a diameter of 0.1 µm, smaller than the 0.3 µm diameter size that HEPA filters promise to filter. The 0.3 µm barrier was established as a benchmark for HEPA filters because particles of this size are notoriously the most difficult to filter. HEPA filters still filter particles down to a size of 0.01 µm, and a 2016 study by NASA³ showed that these filters are very effective at filtering a wide variety of nanoparticles in addition to particles of 0.3 µm or larger as promised. Furthermore, nanoparticles of this size tend to have a random movement pattern, meaning that the likelihood of coming in contact with one of the filter’s fibres is high¹.

Air purifiers: your ally against the spread of airborne viruses

In summary, an air purifier serves as an excellent ally against airborne viruses and pathogens and can greatly help reduce their contamination and spread. It is important to mention that an air purifier does not replace the use of handwashing and social distancing during a pandemic or annual flu season. These methods must be used in combination with your air purifier to ensure protection from aerosol particles that have settled on the skin or other surfaces around the home or office.

Resources

¹ Barnes, C. (2021, October 26). Do air purifiers filter and kill viruses and bacteria? CHOICE. Retrieved November 8, 2022, from https://www.choice.com.au/home-and-living/cooling/air-purifiers/articles/do-air-purifiers-trap-viruses-and-other-germs

² Perry, J. L., Agui, J. H., & Vijayakumar, R. (2016, May 1). Submicron and Nanoparticulate Matter Removal by HEPA-rated media filters and packed beds of granular materials - NASA technical reports server (NTRS). NTRS - NASA Technical Reports Server. Retrieved November 8, 2022, from https://ntrs.nasa.gov/citations/20170005166

³ World Health Organization. (n.d.). WHO coronavirus (COVID-19) dashboard. WHO Coronavirus (COVID-19) Dashboard. Retrieved November 8, 2022, from https://covid19.who.int/