Will air filtration systems protect your staff from airborne virus’s like SARS-Cov-2?
We compare ventilation and air filtration systems and ask the question: Do we need to be thinking about active resistance when it comes to protecting your staff or customers from a build-up of aerosol viral particles.
Since COVID-19 hit our shores concepts that only a year ago were unknown or at best theory are now part of our daily conversation. Who would have thought PPE, nasal swabbing, vaccines, MIQ and air filtration systems would ever become part of our daily conversations or news cycle. Now that we’ve become frighteningly aware of the value of protecting ourselves from the rapid spread of viruses, we need to keep learning – and importantly keep planning – for what comes next by building our own protection layers.
Right now the conversation is focused on vaccination and avoiding lockdowns. Bar a few outliers we seem to mostly understand that we all need to get vaccinated and if we work in certain industries masks may become part of our daily dress code – but is this enough?
What else can we do to protect our loved ones, our work colleagues, our customers?
Do we need better air filtration systems for our indoor environments?
Recently, discussion has been raging among epidemiologists regarding the need for better ventilation systems in our MIQ facilities to help prevent the spread of airborne viruses. The goal of course is to try to work out how to best mitigate the speed and ease with which viruses (especially in this case the virus that causes COVID-19) move from person-to-person. But in technical terms, is it ventilation or air filtration that we need? Or is it even something else entirely? More on that soon.
As we’ve had more time dealing with COVID-19, we’ve seen a shifting focus on our understanding of how people typically catch COVID-19.
Is it touch?
Is it from virus laden droplets that hang in the air?
Is it from surfaces?
Is it from a combination of all three?
In this article we focus specifically on Aerosols and what we can do to mitigate the risk they pose to us.
Reducing the risk of Aerosols
The virus that causes COVID-19 can spread from one person to another in tiny particles of water and virus called aerosols. We make these aerosols when we breathe, and we make more of them when we talk, yell, or sing. Aerosols are different than larger droplets that spread COVID-19. Larger droplets fall to the ground quickly, 1 to 2 metres feet from the person who makes them. Aerosols can stay floating in the air for hours and can travel long distances. Aerosols have less virus in them than the larger droplets, so you have to inhale more aerosols to get sick. But, it’s important to understand that Aerosols can quickly build up in indoor air.
Masks do a decent job at keeping the virus from spreading into the environment, but if an infected person is inside a building, inevitably some virus will escape into the air.
Once the virus escapes into the air inside a building, you have two options: bring in fresh air from outside or remove the virus from the air inside the building.
So how do I stop the build up of aerosolised viruses? There are two traditional methods.
Ventilation or Air Filtration?
By definition, ventilation is the distribution of fresh air to a room, or building. Just about all homes and public buildings have and need ventilation. Stagnant air can be dangerous to breathe, because of the accumulation of airborne contaminants. Ventilation was designed to supply the outdoor air into a building. Ventilation systems don’t remove anything from the air. Instead, they bring in fresh air from outside to replace the stale air in your indoor space. This helps prevent indoor pollutants from building up and results in healthier air.
Air filtration systems, also known as air cleaners and HVAC filters, are designed to filter pollutants or contaminants out of the air that pass through them. Air cleaning and filtration can help reduce airborne contaminants, including particles containing viruses. Portable air cleaners (also known as air purifiers) may be particularly helpful when additional ventilation with outdoor air is not possible without compromising indoor comfort (temperature or humidity), or when outdoor air pollution is high.
Air filtration captures air particles at the source through specialized filters, i.e., HEPA and/or carbon gas filters; and releases clean air back into the environment. One main distinction between filtration and ventilation is that air filtration doesn't bring in the needed fresh air (oxygen) to a building; ventilation does that. Another difference is that there are various types of filters used for capturing different types and sizes of air particles, so not all air filters are capable of capturing the Virus. In order for an air filter to be effective in removing viruses from the air, it must be able to remove small airborne particles (in the size range of 0.1-1 um).
Active Resistance or Reactive?
There are two key issues with ventilation and air filtration which make them both reactive technologies.
They both rely on something called air changes, which is the number of times the air in a space is replenished over time. The lower the air changes and the slower the change the longer the contaminant can ‘sit’ in the air and infect new hosts. In fact ventilation and air filtration can assist in spreading the contaminant as both mechanisms can draw or push the contaminated air throughout an indoor space into previously uninfected areas (and people!!).
While ventilation can dilute the contaminant, and air filtration can trap the contaminant, neither method kills the contaminant. Air filtration also requires a balance between good filtration that will capture contaminants, and airflow. Unfortunately, better quality filtration can lead to a lower airflow.
New options are coming to market all the time, for example UVC light which is often added to an air filtration system and does kill a wide range of contaminants. UVC is a powerful sanitiser however it is still a reactive technology relying on the contaminated air to be pulled past the UVC bulb to be effective.
To illustrate the difference between Active and Reactive imagine a sneeze, laden with SARS-CoV-2 (the virus that cause COVID-19) or even just the common cold or a generic flu virus. An individual (we’ll call him Bob) sneezes in the lunchroom and a number of droplets push past the mask he’s wearing.
The large droplets fall to the table in front of Bob. The lighter droplets spray out at a very fast rate and spread through the room. The Lunchroom is equipped with a good HEPA filter system that draws air into the filter and pushes out ‘clean’ air. The filter system is located in the roof of the lunchroom about 5 metres from where Bob is sitting.
Angela and Jim are sitting at another table in the lunchroom, between Bob and the air intake of the filter system. The air movement draws Bob’s ‘sneeze’ past both Angela and Jim and they breathe in the contaminated air. The ‘sneeze’ is then drawn up into the filter system and captured by the HEPA filter and stopped from being recirculated.
There is an Active Resistance solution.
This is where an Active solution is the next advance in air quality. An ActivePure® system constantly pushes out billions of activated molecules that permeate every part of the indoor space. These molecules actively seek and destroy viruses and bacteria wherever they touch them eliminating the requirement to move the contaminant to a specific place in the room (e.g. filter). To find out more about, how our active resistance technology works, check out the Science behind Active Pure.