01/06/2021 09:32

Covid-19 has changed the way people around the world approach life. Before the coronavirus pandemic, few people cared about the air they breathe. Whether they are on a plane, train, office, hotel, or school, no one took measures to protect themselves and even their families.

Aside from our current predicament, air pollution is a global problem. According to the World Health Organization, an estimated 7 million die every year due to air pollution. The deaths are a result of heart disease, lung cancer, stroke, and acute respiratory infections. Experts point out that the diseases above are typically caused by outdoor and indoor air pollution.

In the advent of the COVID-19 pandemic, many people have asked, can an air purifier filter the Coronavirus? If they do, which are the most efficient? How do they work and how to use them correctly.

In this post, we’ll answer the question – can air purifiers filter coronavirus and more.

Keep reading!

Can Air Purifiers Filter Coronavirus?

Let’s face it. The world is desperate for a vaccine that can help fight the Coronavirus. From Asia to Europe, scientists are spending countless hours developing and testing vaccines that will fight COVID-19.

Meanwhile, in conjunction with other health agencies, the WHO has come up with several measures to reduce the spread of the disease. To protect yourself and others, practice the following:

  • Clean your hands with an alcohol-based hand rub or soap and water.
  • Maintain a distance of 6 feet between yourself and others when in public.
  • Avoid crowded places.
  • Avoid touching your mouth, nose, and eyes.
  • Follow good respiratory hygiene.
  • If you have a fever or difficult breathing, seek medical attention.

While the steps above have helped reduce the spread of the disease. Many people are now obsessed with the idea that air purifiers can protect against Covid-19. The obsession seems to be with indoor air purifiers with fibrous filters like HEPA filter or a UVGI filtration.

So, can air purifiers filter Coronavirus? Before we answer this question, let’s find out more about Coronavirus.

Coronavirus Sizes and Transmission

Globally, scientists placed samples with the Coronavirus virion under an electron microscope. They determined that the virus is spherical with a diameter of 0.12 microns from the electron microscope images. The smallest of the virions is 0.06 microns, while the largest 0.14 microns.

However, the virus can’t spread without a carrier. The virus transmits through respiratory droplets and aerosols from an infected person via coughing, sneezing, talking, or singing. So, transmission occurs in two ways:

Droplets Transmission

  • Larger droplets from an infected person via coughing, sneezing, talking, or singing.
  • Size: 5 – 10 microns, settle quickly.
  • Infection type: close contact, typically within about 6 feet from the source.

Airborne Transmission

  • Smaller aerosols (droplet nuclei) from an infected person via coughing, sneezing, talking, or singing.
  • Size: Smaller than 5 microns, floats in the air for a long time.
  • Infection type: contagious aerosol can travel long distances by air current.

Learn more about COVID-19 transmission from the CDC and WHO.

Can Air Purifiers Trap Coronavirus?

Technically, yes.

Indoor air purifiers commonly use fibrous media filters to blocks particulates. HEPA type (MERV 16) and true HEPA (MERV 17) filter air purifiers are the most common.

The true HEPA (High-Efficiency Particulate Air) filter can trap or remove 99.97% of pollutants with a size greater or equal to 0.3 microns. The HEPA filter consists of pleated fibers.

On the other hand, a MERV 13 grade HVAC filter can block at least 50% of 0.3 – 1.0 microns particles. The potential contaminants (Droplet nuclei/aerosols) ranges in size from 1 to 5 microns.


So, technically a filter with a minimum of MERV 13 ratings can reduce the airborne contaminants by at least 50 percent. The higher MERV rating enables the filter to trap more aerosol and particles.

However, on their own, air purifiers are not enough to protect users from Coronavirus. People must wear masks alongside air purifiers to prevent Coronavirus spread.

When should I use an Air Purifier?

Improve your HVAC system by using MERV 13 or higher grade filters. Make sure the system has negative air pressure. When the ventilation is poor, or the outdoor air pollution is high, a portable air purifier will be useful in an enclosed space. You can use an air purifier for the following circumstances:

  • If someone has symptoms and currently self-isolating at home.
  • In saloons, shops, schools, bars, or where many people gather together for a longer period of time.
  • Inside a car cabin on a long ride (Pro tip: keep the car window slightly open to increase ventilation).
  • To boost the existing HVAC ventilation and filtration.

EPA recommends not directing the airflow from an air purifier such that it blows directly from one person to another. This will aid in reducing the potential spread of droplets containing Coronavirus. They also recommend source control and ventilation.

Source control is where we remove pollutants such as formaldehyde, smoke, and droplets containing the virus.

Can Ionizer Air Purifiers Filter Coronavirus?

Besides MERV and HEPA filters, another technology that helps to remove particles in the air is an ionizer. The ionizer is a common feature in modern air purifiers.

It works by releasing negative ions that attach themselves to particles and droplets, removing them from the air. However, ionizer has a much lower removal rate. They don’t completely remove particles from the room, rather than settle down particles and droplets to the floor, wall, ceiling, and furniture.

The problem is, ionizers generate ozone. Inhaling ozone is not suitable for someone with asthma or has breathing difficulties. While it protects us from UV light high in the stratosphere, it can irritate your eyes, nose, and throat if inhaled.

Should You go for UV-C Air Purifiers?

Many air purifiers have single or multiple UV-C lights to boost air filtration. However, it has been questioned whether it actually works. Research shows that HEPA with UV-C air purifiers effectively removes airborne germs when installed correctly.

If you must buy an air purifier with an ionizer or UV-C, make sure it’s CARB certified.


An air purifier with a HEPA filter can protect you from COVID-19 but in a limited way. This is where face masks come in handy. With a facemask, you and your family can avoid breathing the respiratory droplets carrying Coronavirus. Besides face masks, avoid contact with infected persons.

You and your family should practice strong hygiene practices. That includes washing your hands with warm water and soap or using alcohol-based hand rub. Lastly, seek medical attention immediately if you start coughing or have difficulty breathing.

Stay safe!