How Air Filters & Air Quality Products Affect COVID-19
Running an air purifier indoors and ensuring you replace all of your HVAC filters with high-efficiency filter pads definitely improves the air quality in your environment. Allergens, pollutants and cooking/cleaning fumes are all easily captured by the average HEPA filter, but how do they “stack up” against germs and viruses?
With COVID-19 prevention and social distancing heavy on everyone’s mind right now, many want factual answers to this question. Moreover, if an air filter or purifier doesn’t measure up, how well can masking up in public work? The answers to both questions have excellent responses from both virology experts and the US Centers for Disease Control (CDC).
Examining the facts as presented by experts provide a significant amount of clarity for both questions. Let’s examine the effectiveness of traditional HEPA filtration, electrostatic/ozone-generating air purifiers and UV lighting systems.
Air Filtration and COVID-19
I’ll get right to the point: The only one hundred percent effective air filtration system for COVID-19 is preventing exposure when outside your home. The CDC has studied novel coronaviruses for decades, and their research indicates that individuals can carry the virus on their clothes, skin and hair. How long it survives exposed to open, room-temperature air is still a matter for debate, but the effectiveness of commercial and home air filtration is not.
Microorganisms like viruses are small enough to easily pass through even the finest air filtration systems. This is why social distancing, hand-washing/applying hand sanitizer, using disinfectant wipes on high traffic surfaces (door handles, gas pumps) and wearing gloves are such critical components of preventing the spread of COVID-19. They offer a 99% effectiveness rate when used correctly. Air filters don’t easily trap viruses because the space between the fibers is too wide to properly trap and contain them.
Some might argue HEPA filters can trap particles as small as two microns, and that is sufficient for pollen, most pollutants and allergens. Viruses like COVID-19 are more than a thousand times smaller than even a single micron, measuring in the 0.1-0.3 nanometer range. There is no physical way to make an air filter fine enough to trap viruses and still allow for sufficient flow of breathable air. The fibers may trap some viruses as they pass through, but it is not guaranteed to be effective.
Preventing the spread of viruses via CDC outlined protocols is far more effective since they actively seek to kill the virus on surfaces before it can spread. To make a long story short if you are counting on a HEPA filter to prevent the spread of coronavirus alone, it can’t. There are a few more effective methods of active filtration and purification that may help, but even the best commercial-grade HEPA filter won’t eliminate the virus on its own.
Electronic Air Filters/Purifiers
These devices function by trapping larger particles with a prefilter. Most use some variant of a HEPA filter to eliminate particulates before passing them on into the purification system. This system consists of two electrically charged plates that can collect any material that passes between them at the atomic level (electrostatic air filters). Some electronic air filters also use an ozone generator to trap and kill biological organisms via electrical attachment.
The Journal of Natural Science, Biology and Medicine has confirmed ozone-generating products are effective at killing coronaviruses. Their studies focused specifically on the SARS virus (a corona virus-like COVID-19) and given sufficient exposure time these air purifiers can be as effective as disinfectant or hand sanitizer.
The effects of ozone-generating devices have yet to be tested with COVID-19, so there is no definitive proof they are as effective as they have proven to be when used to prevent the spread of SARS. Using an ozone generating air purifier is unlikely to eliminate the spread of COVID-19, but it certainly doesn’t hinder virus prevention either.
UV Light Purification
UV light systems for air purification and disease prevention number in the thousands, but they all function on the same basic principle. UV Light Purification bathes surfaces in UV light at a specific distance to eradicate biological contaminants. Given a sufficient amount of time, UV light can even kill viruses and pathogens like SARS and MERS.
In air conditioning systems, these UV light bars are placed farther up in the air stream where they won’t affect anyone in the building. Skin-damage is still a very real possibility with prolonged exposure to artificially generated UV light. The effects are similar to what happens to your skin when you are out in the sun for too long, so it’s best to minimize exposure time if at all possible.
UV light systems have proven to be extremely effective at preventing and killing mold, viruses and bacteria on stationary surfaces like damp evaporator coils. That being said, the possibility that they can kill airborne viruses flying past at speeds of 400-450 cubic feet per minute is fairly low.
These UV light bars simply do not have enough time to expose biological contaminants at the correct distance inside an air conditioning system. They are a smart addition to any commercial HVAC system for preventing mold and killing any contaminants that may have attached themselves to the water molecules in the system. Overall, their effectiveness ends there.
All in all, using various methods of air filtration can help slow or prevent the spread of COVID-19, but it’s never going to be as effective as social distancing and other proven methods of disease prevention. Keep washing your hands regularly, avoid touching your face and eyes and use appropriate PPE when out in public. The virus may be small enough to pass through the fibers of a mask, but saliva isn’t.
Most viruses can be spread by coughing with an uncovered mouth up to six feet away. Masks help both asymptomatic and symptomatic carriers prevent the spread of COVID-19 by eliminating that problem. Additionally, if you are exchanging air filters for a home or commercial HVAC system, wear gloves and a mask to prevent accidental exposure to any viruses that may be trapped in the filter.
Air filtration systems may have limited effectiveness against the spread of COVID-19, but the effectiveness of traditional virus prevention protocols is irrefutable. Until the next time, stay safe and keep following CDC guidelines in public, at work and at home.