The Keys to Combating COVID Or Any Other Airborne Pathogen: Ventilation & Filtration
What do COVID-19 super-spreader events have in common? Poorly ventilated spaces. Experts say small changes can have big impacts on safety.
Why do COVID-19 cases spike during indoor gatherings? Infection risk peaks when virus particles concentrate over time in poorly ventilated indoor air. Many buildings where people gather—such as homes, schools, restaurants, and offices—are not equipped with the ventilation and filtration systems needed to prevent the spread of COVID-19, experts say. “People are familiar with masks, handwashing, and social distancing, but fewer people are aware that ventilation and filtration really matter.” -Dr. Joseph Allen, Director of Harvard Health’s Building Program in the Wall Street Journal.
How COVID-19 spreads through the air
Why are indoor gatherings so dangerous? It is primarily due to virus particle accumulation. Airborne virus particles or aerosols are released every time we breathe, talk, or cough. Indoors, each room we inhabit is like a box where particles accumulate over time. In each “box,” studies show that virus particles:
- Float up to 16 feet—well past ‘social distance’
- Remain airborne for hours
- Stay infectious for up to 3 hours
According to Dr. Erin Bromage, a Dartmouth Immunology and Infectious Disease professor, indoor spaces account for 90% of all transmission events. So, any enclosed environment with poor air circulation and a high density of people spells trouble.
An open letter from 239 international scientists to the World Health Organization stated:
“Viruses in aerosols can remain suspended in air for many seconds to hours, like smoke, and be inhaled. They are highly concentrated near an infected person, so they can infect people most easily in close proximity. But aerosols containing infectious virus can also travel more than [two meters] and accumulate in poorly ventilated indoor air, leading to superspreading events.”
Three things we know about COVID-19 infection:
- It’s airborne. While handwashing and surface disinfection were the early focus, we now know the virus is primarily transmitted by breathing air shared with those who are infected.
- Masks and distancing, while reducing risk, will not fully protect against virus transmission indoors because the longer a group is together in a shared space, the greater the risk of infection.
- Removing virus particles quickly from indoor shared air spaces, without relying upon constant mask-wearing, is one reason why the CDC and EPA recommend in-room air purifiers.
What is air exchange and how does it reduce COVID-19 risk?
Even small indoor gatherings can quickly become super-spreaders. Why? Poor air exchange. Air exchange, measured by Air Changes Per Hour (ACH), is the total amount of “clean” air entering a room. We know that COVID risks are lower outdoors because natural air exchange disperses virus particles.
Here’s the problem when things move indoors: Most home heating, ventilation, and air conditioning (HVAC) systems recirculate indoor air mixed with outdoor air. When it’s very cold or hot outside, HVAC systems recycle far more indoor air because they’re not powerful enough to quickly heat or cool enough outdoor air.
Many people are beginning to realize that their buildings can’t respond to this risk with air exchange systems that are not dynamic or resilient, and whose capacity cannot be easily increased.
Recirculated air contributed to nearly all documented super-spreading events. In New York, contact tracing has shown that 70% of new cases come from small gatherings.
The proven way to mitigate virus concentration is by pumping in clean air. But what if you can’t open windows or rely on HVAC?
Consider supplemental air cleaning/purifying with a portable air cleaner/purifier with or without a HEPA filter and/or a filter that has been treated with Zetrisil®. Be aware that HEPA filters do not kill viruses, bacteria or other pathogens. HEPA filters are designed to remove, from air circulation, particles of a particular size and trap them in the filter. The pathogens remain on the filter and can pose a risk when changed and replaced. Filters treated with Zetrisil®, however, will actively kill viruses, bacteria and other pathogens as they pass through the filter. Sized properly for a room, a restaurant, a school classroom, a bedroom at home, or other enclosed space, an air cleaner/purifier can achievet 4, 5, or 6 air changes per hour of clean air on a very cost-effective basis.
Recommended Air Purifier
Our recommendation for achieving clean air starts with an Air Purifier Model SD-AP180A1. This small footprint, six-step filtration air purifier can easily handle a room up to 645 square feet in size. We also recommend treating the air filter once a month with our Zetrisil® infused sanitizer/disinfectant. As the air passes through the filtration system, airborne pathogens will attracted to the surface where they will be effectively destroyed. A major cornerstone of safety from dangerous pathogens is CLEAN AIR !!!