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Do Air Purifiers Kill Viruses?

The effectiveness of air purifiers in reducing viral load in indoor environments [1] makes them a hot commodity for commercial, industrial, and residential spaces. 

Air purifiers for viruses peaked in popularity during the recent global pandemic because of their ability to help keep indoor air sanitized as part of overall mitigation efforts.

The growing frequency of wildfires on the West Coast continues to keep air purifiers in the spotlight. In 2020 alone, California had five of the six largest wildfires in most recent history, including a record cluster of megafires. 

Once a rare occurrence, megafires have become more prevalent due to climate change [2]. This is bad news for residents who live in wildfire-prone areas. 

A new study [3] from a team of researchers at Harvard University suggests that exposure to elevated levels of fine particle pollution from wildfires can increase the likelihood of dying from SARS-CoV-2 (COVID).

Whether you live in a wildfire zone or not, it is worth exploring the many benefits of using an air purification system to help keep your indoor air quality healthy and free of harmful volatile organic compounds (VOCs).

 

Viruses That Are Found Indoors

COVID is not the only virus that can linger indoors and make you sick [4]. The common cold and flu viruses also love closed-in spaces where they can infect the most people in the shortest period. 

When ventilation is poor, it contributes to the spread of viruses by allowing them to circulate throughout the room more easily [5].

When someone coughs or sneezes, tiny droplets filled with bacteria and viruses scatter in the air. People nearby can inhale those droplets, which can cause them to become sick. It is a vicious cycle that can be mitigated with a high-quality air purification system.

If the person were to sneeze or cough into their hands instead of a tissue or their elbow, they now have viruses and bacteria on their hands, which can spread to common surfaces like doorknobs and handrails. 

Anyone who touches those surfaces while the virus is present and then touches their eyes, mouth, or nose could become sick. While a quality air purifier can help catch airborne bacteria and viruses, it’s important to note cleaning common surfaces is still required to kill the invisible bacteria and viruses clinging onto the surfaces. 

 

HEPA Filtration For Virus Control

Do air purifiers kill viruses? Some top-quality air purification systems can kill viruses, but it is more accurate to say they trap them. Eventually, the virus will die if it is unable to escape the clutches of the air filter. 

Air purifiers that use carbon filters and HEPA filtration systems can safely catch viruses on the surface of the filter and hold them there. 

If you have to choose between a carbon filter unit and one with HEPA filtration, HEPA filters are more effective at sanitizing the air. Choosing one with a high MERV rating guarantees efficacy. 

Most quality air purifiers for residential use have MERV (Minimum Efficiency Reporting Value) ratings between 1 and 20. The ideal MERV rating for residential spaces is at least 13.

Can an air purifier remove viruses? The short answer to this question is yes, but there is a caveat. Air purifiers can only remove viruses that are already airborne. 

Any viruses clinging to surfaces in your commercial, industrial, or residential spaces will remain there, even with a high-quality air filter running around the clock. Surfaces must be sanitized with a cleaner proven to kill bacteria and viruses to rid those spaces from becoming infection sources.

 

Air Purifiers For Virus Control Indoors

Do air purifiers get rid of viruses? Can an air purifier remove viruses from an indoor environment? Yes, if you buy a high-quality model. 

Consumers have to be careful when choosing an air purifier because they are all not created equally. Some are effective at trapping and killing viruses, while others simply recirculate them. The key to finding a high-quality air purifier is in the filter.

Choose an air purifier that uses a HEPA filter when possible. HEPA filters capture bacteria, particulate matter, and viruses as they travel through the air. Top-end air purifiers have HEPA filters that remove 99.97% or more of airborne particles with a size of 0.3 microns or larger. 

It is important to verify you are buying an air filtration unit that has a true HEPA filter and not a HEPA-like filter. There is a huge difference. To be labeled a true HEPA filter, it must meet HEPA standards [6] as developed by the American Society of Heating.

 

How To Use An Air Purifier When Someone Is Sick

Air purifiers for viruses can help control the transmission of viruses indoors.

When air purifiers and viruses are in the same space, it can help reduce transmission. If someone in your household is sick, using an air purifier designed to trap and eliminate viruses from the air can reduce the chances others will become ill [7]. 

Incorporating an air purifier as part of your disease prevention strategy can help when you follow these guidelines from the US Centers for Disease Control and Prevention:

  • Isolate the person who is ill from the rest of the household.
  • Place an air purifier no further than 3 feet from the person who is sick.
  • Run the air purifier 24/7 on the highest setting the person can tolerate.
  • Keep the air purifier clear from anything that can obstruct airflow like curtains and furniture.

If you must change the filter while the person is still sick, wear a mask and gloves and take the air purifier outside before opening it to remove the filter. Disinfect the surface of the air purifier before putting a fresh filter in the unit.

 

References:

[1] Air purifiers: A supplementary measure to remove airborne SARS-CoV-2, Bin Zhao et al, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7180358.

[2] Megafire, National Geographic Resource Library, https://www.nationalgeographic.org/encyclopedia/megafire.

[3] Wildfire smoke may have contributed to thousands of extra COVID-19 cases and deaths in Western U.S. in 2020, Harvard T.H. Chan School of Public Health, https://www.hsph.harvard.edu/news/press-releases/wildfire-smoke-may-have-contributed-to-thousands-of-extra-covid-19-cases-and-deaths-in-western-u-s-in-2020.

[4] Ribeiro, Edna et al. “Viruses Present Indoors and Analyses Approaches.” Exposure to Microbiological Agents in Indoor and Occupational Environments 129–155. 12 Jun. 2017, doi:10.1007/978-3-319-61688-9_7

[5] “Indoor spread of COVID-19 can be lessened, experts say,” Center for Infectious Disease Research and Policy, May 28, 2020, Mary Van Beusekom.

[6] United States Environmental Protection Agency, “What is a HEPA Filter?”

[7] Air Cleaners, HVAC Filters, and Coronavirus (COVID-19), U.S. Environmental Protection Agency (EPA).