(Last Updated On: March 24, 2023)

A straightforward look at the complexities of capturing viruses

With the global outbreak of novel coronavirus (COVID-19), many are wondering whether air purifiers can help combat airborne viruses. Amid much confusion and misinformation, we want to clear the air and provide some useful facts, not to mention a few tips for staying safe. 

Our greatest enemy right now is not the virus itself. It’s fear, rumors, and stigma. And our greatest assets are facts, reason, and solidarity,” said World Health Organization Director-General Dr. Tedros Adhanom Ghebreyesus.  

First and foremost, if you believe you or someone in your household might have COVID-19, take immediate action by following the Centers for Disease Control and Prevention (CDC) guidelines.   

The Facts 

Can an air purifier capture coronavirus? To a degree…Yes. An air purifier equipped with a HEPA (high-efficiency particulate air)-rated filter can technically capture a portion of airborne virus-sized particles. Once trapped, viruses cannot multiply on their own or remain infectious for long. But NO air purifier can completely protect you from a virus.    

We believe air purification provides additional support to your body’s most important tool for fighting viruses—a healthy immune system. It’s a passive, “always-on” way to improve the overall health of a breathing space that doesn’t require major lifestyle changes. 

 In this article, we’ll break down the following: 

  • HEPA filtration technology
  • How current HEPA air purifiers can remove a portion of viruses sized particles from the air
  • How long COVID-19 can survive in your home
  • How purifiers benefit your immune system & support a virus protection plan
An image of the first case of the novel Coronavirus (COVID-19).
An image of the first case of COVID-19, courtesy of the CDC.
Coronavirus’s name comes from tiny spikes that resemble a solar corona.

How HEPA Really Works

Originally developed in support of cleanrooms for atomic energy development, the U.S. Department of Energy (DOE) created HEPA as a specification for suppliers of filtration products based on particle removal effectiveness (e.g., 99.97% at .03 microns and above). Filters are commonly perceived as nets or a screen that will stop objects larger than the smallest holes while letting air through. 

HEPA filters work much differently that how a fly gets trapped on a screen, as pictured. HEPA filters trap particles much differently than a simple screen or net.

Here’s the reality: HEPA filters are a complex weave of tiny fibers that carry an electrostatic charge which attracts bypassing particles—more like a magnet than a net. The smaller the fiber with the greater charge coefficient, the greater the likelihood of trapping ever smaller particles. All of this is effective to the extent that air can be channeled through enough filter material without air bypassing around it.

An extreme close-up of HEPA material. Note the irregular, maze-like weave. An extreme close-up of HEPA material, courtesy of Engineering360.

How Do HEPA Air Purifiers Capture Viruses? It’s All About Physics 

The most current state of the art in filter material is referred to as True HEPA or H13 by the DOE. True HEPA removes 99.97% of particles at .03 microns or higher, but this is a helpful yet incomplete description of HEPA capability. Even though some of the particles (like the COVID-19 and H1N1 flu viruses) will bypass the filter—a portion of those will be trapped due to the charged magnetic effect of HEPA fibers.

Further enhancing capture of tiny virus particles—which can be over 100 times smaller than particles like dust, pollen, and dander—is a phenomenon known as Brownian Motion, in which microscopic particles bounce around in zigzag patterns and get trapped in HEPA’s maze-like fibers.

A diagram showing the range of particulates a True HEPA filter can capture
A diagram showing the size range of airborne particles.

But here’s the important take away: Although HEPA is a DOE specification, testing and manufacturing protocol in the consumer sector varies to the extent that no purifier brand should claim they can completely protect people from COVID-19. Air purifiers are an additive protective measure if properly sized to a room.

HEPA filters can remove a portion of airborne particles such as COVID-19 and other flu viruses. But the extent of removal that may be truthfully claimed can only be done by proxy tests in controlled environments, which are still underway.

With current HEPA technology, 99% or more of airborne virus particles in a room cannot be removed by an air purifier nor by other means that have yet to be proven. Of course, this would also not include virus particles that remain alive for periods of time on surfaces open to touch.

How Viruses Spread & Why Air Purifiers Can Help  

COVID-19 spreads by close person-to-person contact, especially when an infected person coughs or sneezes, according to the CDC. Virus particles are attached to and carried by water vapor, which are tiny droplets that float in a fine mist. Coughing is one of COVID-19’s main symptoms, so airborne transmission is a big concern.

The only way to reliably remove virus sized particles from the air is by circulating the entire volume of air in a room or enclosed space multiple times per hour to increase the likelihood that nearly weightless virus particles will enter the airflow of a filter.  

To work effectively, a purifier must circulate air throughout your entire room.

Since health experts are advising more and more people to stay home, a HEPA air purifier can play a significant role in minimizing airborne transmission and supporting overall wellness.

Why Filtering Airborne Viruses is Just One Part of Prevention 

Given justified concerns over the spread of COVID-19, there are some who have suggested that air filtration is ineffective and instead make other recommendations. We believe this is a false dichotomy. Protective measures are both reasonable and cumulative; both/and rather than either/or. Why not take an all-of-the-above approach to virus protection?

Yes, we sell air purifiers and have for 15 years, but we will be the first to recommend additional means of wellness and immune system support in addition to breathing pure air. For example, transmission by physical contact can only be addressed by other non-airborne measures.  

COVID-19 can remain infectious for three hours when aerosolized into floating particles, like a cough or sneeze, according to a new study. On surfaces, it remains viable for up to three days.

Likewise, “viruses can’t multiply on their own—they must infect the cells of a living creature,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, told PBS.

What this means is that viruses trapped in an inorganic HEPA filter will stay there and die without further harmful effects. But since COVID-19 can live for up to three days on surfaces, it’s critical that you follow ALL the CDC’s guidelines to prevent illness.

How Air Purifiers Support Immune System Health + Tips to Stay Well

Each airborne particle you inhale—whether it’s a pollutant, allergen, or pathogen—triggers a response by your immune system. By capturing those harmful particles and circulating clean air throughout your space, your body can focus on keeping your immune system strong day and night.

Breathing air that’s free from harmful particles is just one part of a wellness plan that should include ample sleep, plenty of purified water, good hygiene, and a balanced diet.   

According to the CDC, here are the top seven ways to protect yourself from COVID-19 every day: 

  • Wash your hands often with soap and water for at least 20 seconds, especially after going to the bathroom; before eating; and after blowing your nose, coughing, or sneezing.
  • If soap and water are not readily available, use an alcohol-based hand sanitizer with at least 60% alcohol.
  • Avoid close contact with people who are sick.
  • Avoid touching your eyes, nose, and mouth.
  • Stay home when you are sick.
  • Cover your cough or sneeze with a tissue, then throw the tissue in the trash.
  • Clean and disinfect frequently touched objects and surfaces using a regular household cleaning spray or wipe.

Information about how to spot and prevent spread coronavirus from the CDC

Bottom Line

Air purifiers alone will not protect you from viruses, but they can contribute to an overall healthier indoor environment and better sleep. A purifier’s effectiveness depends on its ability to draw in contaminated air and circulate pure air throughout your entire breathing space or ‘box.’ AirPurifiers.com is proud to sell top-rated purifiers that do just that—quietly and efficiently.  

Your wellness is our highest priority. Our air quality experts are available to answer your questions 8 a.m. to 6 p.m. CST M-F and 10 a.m. to 4 p.m. Saturday. Call 800-497-8263 or email [email protected].