Below is a list of the most common Air Filters and Indoor Air quality products for residential homes. We are trying to gear this to answer the questions on the benefits that each product does provide, but also let you know how it might affect the Covid-19 disease and your chances of getting it.
Can an Air Filtration System Protect from Covid-19?
Ultimately no matter what filtration system you have, the only way it can filter out any virus is if you or somebody you know first bring the virus into your home. If you were truly being as careful as some suggest, such as washing your hands and changing your clothes every time you leave the house, the only other way we can think that you would bring it into the home is unfortunately in your lungs. No filtration system will clean your lungs, nose or mouth if that is where the virus is hiding so please be very careful as your money and time is better spent making sure you have personal protection equipment when you go out such as disposable gloves, hand sanitizer, wipes for things like gas pumps and door handles, and a mask (preferably N95 or better).
Standard filters are unlikely to be of much assistance in capturing viruses of any sort. The viruses are too small and pass easily through the gaps in the filters. It is possible that something such as a virus or bacteria can be trapped by the filter if it hits the filter just right, so use gloves when removing an old filter and place it directly into a sealed trash bag. Remove it from your house and set in in your outdoor garbage can.
Types of Air Filters and Their Effectiveness Against Viruses Like Covid-19
High Efficiency Air filters
There are HEPA like filters that can capture particles as small as 2 microns. They will filter out most dust particles, allergens, pet dander and mold. Most Viruses are too small and unless they somehow get trapped by directly hitting the fibers in the filter, then it is likely that at least some of the virus will pass right by and continue into the air distribution system. Even true HEPA filters will only filter out completely microns down to .3 microns with 99.97% efficiency rate. Since viruses are much smaller than this they can pass through even true HEPA filters. Hospitals are usually the primary purchasers of true HEPA filters, but even they do not rely solely on these filters to clean and sanitize their air.
How HEPA filters work for Covid-19
Again, the virus is small enough that it can pass through the filter. Some of the virus may get caught in the filter, but we cannot sell this product under the banner that it will protect you from Covid-19
Electronic Air filters
Electronic air cleaners work by trapping most particles traveling with your air in a prefilter. Anything that gets past the prefilter goes to an electrically charged filter. The contaminants that were too small to get caught by the prefilter are charged by the electronic air filter and are sucked into the oppositely charged plates that are part of the filter. Some electronic filters will have another portion that creates ozone. The oxygen molecules created by the ozone generator will attach themselves to contaminants such as mold spores and bacteria and eliminate them.
How Electronic air filters work for Covid-19
According to the journal of Natural Science, Biology and Medicine, ozone generating products will kill coronaviruses and is documented to have been effective against SARS (Another coronavirus similar to Covid-19). Where ozone has been tested against many viruses it can be as effective at damaging or destroying up to 99% of virus cells when exposure amount and length of time to ozone is sufficient. Ozone has not been tested specifically on Covid-19, though, so we cannot say definitively that it will kill this new virus.
What the EPA Says on the Effectiveness of Ozone
The EPA says the following about the effectiveness of ozone, “Some data suggest that low levels of ozone may reduce airborne concentrations and inhibit the growth of some biological organisms while ozone is present, but ozone concentrations would have to be 5 – 10 times higher than public health standards allow before the ozone could decontaminate the air sufficiently to prevent survival and regeneration of the organisms once the ozone is removed (Dyas, et al.,1983; Foarde et al., 1997).”
There are many different versions/types/manufacturers of UV lights in the United States and elsewhere. They all work under the same basic principal. They bathe surfaces in UV light at a particular distance and with enough time, can kill viruses such as SARS and MERS. The key point here, though, is time. It takes time under UV light for the UV rays to damage the DNA sequence and kill the virus. UV lights in homes are stationary and are mounted somewhere in the air stream where it can never shine directly on a person. Just like too much UV light from the sun can damage your skin, man-made UV lights will cause harm to a person when exposed to it for any length of time. They are very good at killing viruses, mold and bacteria on a stationary surface such as a wet evaporator coil. If we think of how a virus such as covid might travel in a ducting system where the air is traveling at 400-450 cubic feet per minute, the stationary UV light would not have the time to kill the virus as it passes by the light in the ducting system.
How UV lights work for Covid-19
As mentioned above they have been proven to work on viruses such as MERS and SARS (these are also coronaviruses). Although UV light has not been proven to kill Coronavirus as of the date of this article, it is highly likely that it will kill the virus with enough time and the proper distance to the virus. Having said that to get the proper distance and the amount of light needed to kill the virus will also do a lot of damage to you personally so you should never try to disinfect yourself or a surface with a UV light that you will be exposed to as well. UV lights have a place in sanitizing ducting or equipment evaporator coils, but that is because they will never expose people to harmful rays. They are not very effective at ridding any virus from the ducting system as they are not likely to be exposed to the UV light for a long enough period to do damage.
Here again there are many different manufacturers for air scrubbers. The Aerus Air scrubber uses what they call ActivePure Technology to sanitize the air. Here is a chart to show you how long it takes to clear specific contaminants.
The way this system works is microscopic oxygen and water molecules in the air enter the purification unit and pass through the Active Pure Honeycomb Matrix. While inside this unit, the molecules are turned into powerful oxidizers that are released back into the airstream. This allows the oxidizers to go attach itself to contaminants both in the air and on surfaces within the home. The oxidizer then kills many contaminants including such things as E. coli, Staph, Strep, the avian Bird Flu, and the Swine Flu within 6 hours of treatment in most cases.
The advantage this system has over the others is that it sends out VOC killing molecules to attack them where they are as opposed to the others who have to rely on the HVAC system to bring the contaminants to them. There are also commercial models that will create ozone that can also travel in the airstream and eliminate even more contaminants.
How Air scrubbers work for Covid-19
Like all of the products listed in this article, this one has not been tested specifically on Covid-19. We feel like it has more advantages and opportunities to kill viruses, bacteria, mold and other VOC’s as the product it uses to kill the contaminants is also airborne and can go to where the contaminant is. Some of these models also include UV lights for a little added protection. Of all the products we feel this has the highest value, but it is also the most expensive.
How Effective are Air Filter Systems Against Covid-19?
Key points/advice to our customers
- No product commonly used for consumer air filters and indoor air quality products has been tested for effectiveness against Covid-19
- Most of these products are effective in some way against coronavirus type viruses, but not in all applications and all but one are reliant on the air ducts to both bring the virus to them and hold them in place long enough to kill them. This is a highly unlikely scenario.
- Indoor air quality is very important to your overall health and we would strongly recommend some of these products to improve your indoor air quality, but we don’t think you should think of them as a way to prevent you from getting the virus
- Above all else educate yourself on the product you are being pitched. Use common sense. If it sounds too good to be true it most definitely is. Don’t panic buy toilet paper, canned goods, or IAQ products.
One other thing to think about is many of these products such as the HEPA filters (or any high efficiency filter) is going to restrict your airflow. A static pressure reading has to be taken prior to installation and often time duct modifications are necessary to keep the system running properly. If the static pressure (resistance to airflow) gets too high, your systems components such as the compressor and ECM motors can fail prematurely. Most of the things listed above should not be attempted to be installed by anyone other than someone familiar with the product and your HVAC system.
Please feel free to call us anytime for more information.