Air, not surfaces

Covid-19 is airborne. It has become my favourite Twitter hashtag. I use it every chance I get because we cannot scream it loud enough. Say it with me: COVID is Airborne.

This has been known and talked about for a year by leading public health, building science, and indoor air quality experts. People like Dr. Joseph Allen, Dr. Kimberly Prather, Dr. Linsey Marr, Dr. Richard Corsi, and others whom I’m completely forgetting right now, have been saying it out loud – in interviews, in print, and online – since early in the pandemic.

ASHRAE issued guidance in May 2020 that compared its position with that of the CDC and WHO, noting that aerosol transmission needed to be addressed. In January, they issued new recommendations for dealing with airborne infection. On April 5th, ASHRAE yelled it out loud. In fact, they used the word “unequivocal” in the press release.

But the CDC has been reluctant to say that COVID-19 is definitely transmitted through aerosolization until now. Guidance was updated on building ventilation a few weeks ago, and on surface transmission this week.

Early on, it was believed that droplets were the key vehicle for spread of the virus, and so surface cleaning became the focus for everyone. We washed everything that came into our homes. We washed our hands and sanitized after touching any surface. All of this was to prevent the spread from hands to face, especially to the eyes, nose, or mouth which provide a pathway for germs into your body. That remains important, but now we know much more about how transmission happens.

Studies now definitively show that Covid-19 is transmitted through the air, not in larger droplet form but as aerosols that can travel further from the source. That fact has shifted the focus much more onto HVAC systems and air inside buildings: ventilation rates, filtration, and bringing in fresh outdoor air. It also shifts attention to the design of buildings and their systems, and to Architects and Engineers.

There is much to do to make buildings safer, not just right now as we continue to battle this pandemic, but for the future.

Just as Covid-19 immediately revealed inequities in our communities last year, now we can see issues of equity within buildings. Inequity takes the form of years of deferred maintenance in public schools, poor indoor air quality and overall quality of life in shared or public housing, and conditions inside industrial facilities such as meat processing plants.

Fixing all of that is, well, infrastructure. It’s not just about roads and bridges. Infrastructure encompasses everything that makes up the framework supporting our communities: housing, schools, broadband, public transit, and of course roads and bridges. Everything. Because it is all connected.