Air purifier and coronavirus: How effective an Air purifier is against virus?

air purifier

In the time when world is fighting against COVID-19 pandemic, all that everyone is thinking is safety of oneself and family. Adhering to the government guidelines and being self alert is the key for preventing the spread. Since coronavirus can be present in air in droplets forms, it become the obvious question that how effective an Air purifier is against coronavirus?

Air purifiers can help reduce airborne contaminants including viruses in a home or confined space. 

In order to understand this let’s see how the Air purifier works.

Air purifier working

Air purifier cleans the air within a specific area through a specialised filtering process that targets microscopic particles that poses harm to our health, Humans in particular.

Air purifiers have two basic component. Fan and Filter. It uses fans to draw in air and pass it through a filter before expelling the purified air out the other side. They’re effective at removing odors and large particulates from the air.

air purifier working

There are different type of air purifier depending on filtration technology. Among these high-efficiency particulate air (HEPA) purifier is considered as the best purifier that traps around 99.97% of pollutants having size as small as 0.3 micron. Although this collection efficiency is impressive, it is not absolute; depending on conditions, 0.03% of matter at the most penetrating size does penetrate the HEPA filter.

Air inside house may contain various type of contaiminations like

air pollutants

Most of these get filtered out by HEPA filters including bacteria and viruses.

“In theory, if an air purifier removes viruses from the air, it reduces concentrations in the room and thus reduces the potential for exposure,” says Linsey Marr, an environmental engineer and professor at Virginia Tech who specializes in airborne disease transmission, air quality, and nanotechnology. “So there is a mechanistic reason to think that air purifiers could help reduce transmission.”

In 2003, during the SARS outbreak, the Hong Kong Hospital Authority recommended hospitals use portable air purifiers with HEPA filters to help reduce transmission to healthcare workers if isolation wards were not available. 

But here is the catch,

The COVID-19 virus is approximately 0.125 Micron or 125 nanometers in diameter.  (Source: National Library of Medicine). Which is beyond filtration limit of Air purifier having powerful filter like HEPA filter. However, it often travels in biological aerosols from coughing and sneezing which range in size from 0.5-3 Micron. This size easily captured by HEPA filters.

If you are having impression that air purifier works like net and it filters out those pollutant having larger size, that is not the complete picture. there is whole lots of science involved in that.

Smaller particles like coronavirus, and other nano-particles get captured using a scientific phenomenon called diffusion. Diffusion is proven to be surprisingly effective at capturing tiny virus-sized particles. According to NASA, HEPA filters capture “virtually 100% of particulates.” Researchers have shown that HEPA filters are incredibly effective at capturing nanoparticles–even smaller than the coronavirus.

So are all HEPA filter based air purifier can be equally effective?

In this, CADR (clean air delivery rate) plays crucial role. CADR is the volume of clean air that an air purifier produces at its highest speed setting. The faster an air purifier can cycle air through the filter, the better its chances of catching virus particles.  Any air purifier with a CADR > 240, can perform roughly five air exchanges per hour in its suggested room size. That should be the minimum requirement while your are looking for HEPA filter based air purifier for protection from coronavirus.

HEPA filter based air purification is used in airplanes and hospitals also that guarantee high level air quality. They are subjected to regular maintenance and checkups. Filters traps virus and they may get pileup if not cleaned and maintained properly.

Maintenance of Air purifier for ensuring safety from virus

Following are the basic precautions that can be taken at home for ensuring maximum protection from virus including coronavirus.

  • Since coronavirus can live on plastic and steel, take extra precautions when handling the air purifier and changing the HEPA filter.

  • Avoid touching air purifier while it’s in use, and when it’s time to change the filter, put on gloves and a surgical mask, clean and disinfectant the exterior. 

  • Keep the air purifier separated from anything that can obstruct airflow, such as curtains or furniture, and keep the door to the room closed.

  • Even the most efficient air purifiers can’t prevent some droplets from landing on floor surfaces, where they can live for hours or even days so you should clean your home and wash your hands  regularly.

According to dyson, which is global leader in air purifier ” Dyson air purifiers will capture viruses, but won’t destroy them. The virus will remain alive inside the filter for as long as the virus survives.” as reported in digitaltrends.

So what should be the preferred choice while looking for air purifier?

Obviously true HEPA filter, higher CADR rate, Low noise level and electricity consumption, appealing built feature, low cost maintenance etc should be in your list.

HEPA filter based Air purifier

Here are the recommendation of HEPA filter based air purifier based on our analysis of various product available in market

  • Dyson Pure Cool Air Purifier: Air MultiplierTM technology | Vaccum sealed 360 degrees Glass HEPA Filter | CADR of 360 m3/h | Humidity and temperature sensor 

You are using any other existing filter in your home don’t forget to share your feedback.

Stay safe.


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