Assessing & Improving Indoor Air Quality in the COVID Era Buildings Need to Breathe

COVID-19 has caused more far-ranging, persistent anxiety than any other event in recent history. It has affected our jobs, our living situations, and the way we interact with others, and it’s not done with us yet. Scientists and public health experts are still refining their understanding of the way the virus spreads, but one thing they have determined for certain is that the novel coronavirus spreads through the air - especially within enclosed spaces - and does so far more easily than it does outdoors, or via surface contact.   

“Outside is better than inside,” has become a refrain among health experts. And fortunately, in these summer months most of us can go outside safely on most days. We can maintain social distancing to provide protection from infection.  We can wear a mask. (And to the city’s great credit, the vast majority of New Yorkers do wear them.) But the dog days of August still lie ahead. What happens when the weather is just too hot for outdoor activities or open windows? And what happens after that, when the weather turns cold, and open windows and outdoor forays become impossible for the opposite reason? Among the seemingly-endless questions we all have about the virus is how it behaves in more or less enclosed spaces when HVAC equipment is running to either heat or cool those spaces. 

Air Conditioning & COVID-19

Transmission of the novel coronavirus is thought to happen mainly through large droplets expelled from a carrier’s mouth and nose during coughing, sneezing, or talking. Evidence also suggests that at least some cases of COVID-19 occur via airborne transmission. That happens when virus particles contained in smaller droplets don’t quickly settle out and fall to the ground within six feet of the carrier who expelled them, and instead hang in the air and drift around on currents - posing a threat to anyone who happens to walk through one of those currents. Airborne transmission is thought to have been a factor in the coronavirus’ spread among members of a vocal choir in Washington state, through an apartment building in Hong Kong, and in a restaurant in Wuhan, China.

Drawing on what we know about how tuberculosis - another deadly airborne disease - is spread, Dr. Edward Nardel, an infectious disease expert affiliated with Harvard University, suggested recently in an interview for The Harvard Gazette that air conditioning use across the southern U.S. may well be a factor in that region’s recent surging COVID-19 cases. But while expert consensus is that HVAC equipment does have the capacity to spread the virus, questions of what exactly to do about that remain. What precautions can we take to protect ourselves?  

One facts-based option to make air conditioning systems safer is to use high-efficiency filters to essentially strain dangerous contaminants out of the air before they get to anyone’s lungs. Peter Catapano, a mechanical engineer with O & S Associates, a national engineering firm based in Hackensack, New Jersey, says the answer lies in high-efficiency particulate air (HEPA) filters, an existing technology currently used in all kinds of medical facilities to filter out many bacterial, fugal, and viral particles.


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  • What about pre-war residential buildings where there are on very few windows in the lobby of buildings, common areas? .Especially when winter comes and doors /windows are closed. Not to mention elevators! What is the real solution with these limited situations ?. Thank you
  • Air conditioners have been around since the early 1900’s. Since the 60’s through wall & window ac’s became popular where HVAC central air / heat & split ductless systems have become more popular with time. What we’ve learned over more modern years is that the tons of cubic feet of air that’s pulled into these small, concentrated ac units gets caught inside them. Mold evolves along with dust, dirt & debris. This has been collecting inside condensers, compressors, coils, fans & any passageways this blowing air travels. It’s not rocket science that we’ve been breathing this air with varied amounts or types of mold spores within it for many years. Some are less sensitive but many people have & still do get ill from it. The issue with COVID only exasperated our understanding of what was always an issue. Just like the past when few considered the dangers of smoking cigarettes we’ve paid little or no attention to an issue which has made a large % of our population unhealthy; some getting seriously sick. This issue with mold & who knows what else inside these little units sucking in & recirculating astronomically massive junk in our air where the build up clogs these devices should not be concidered a now-or-never emergency. After all you’ve been breathing it for a long time & you are alive, probably healthy. However if we’ve learned anything from pandemics, new technology & old beliefs of our diets, importance of fresh water or how cigarettes & so many other consumables are toxic or cause is this: We can act to prevent it. We do learn, can & will protect ourselves as necessary, especially if we’ve isolated these causes or logically diagnosed these malefactors. In time we all grow, evolve, recover, survive... and flourish.