Thread by @opinion

Covid-19 has taught the world quite a few things.

Not least, the value of fresh air. Better ventilation in workplaces, gathering spaces and other public buildings should be a post-Covid priority trib.al/r3TTvqC

Schools, offices and other indoor spaces need better ventilation in order to minimize the harm from:

🦠New coronaviruses
🦠Cold and flu viruses
🦠Every other sort of airborne pathogen trib.al/r3TTvqC

Covid calls for rethinking the way indoor air is controlled.

✅New guidance on safer ventilation in schools is urgent
✅State and local building codes should also be revised
✅Effective ventilation, which often requires more energy, can't be ignored twitter.com/i/broadcasts/1…

Most big systems for heating, ventilation and air conditioning circulate air quite slowly.

Typically, most of the air in a room changes about twice an hour.

It's imperative to clear exhaled virus particles from a room full of people trib.al/r3TTvqC

"Displacement ventilation” is needed. This sends cool air through vents low in the room and draws out warmer air through the ceiling.

Some hospitals and other buildings have these systems. They should be preferred in new construction trib.al/r3TTvqC

Displacement ventilation should be preferred in new construction. But what about existing buildings that aren’t already equipped?

More research is needed on using filtration and ultraviolet irradiation to minimize the risk of infection trib.al/r3TTvqC

How well plug-in ionizers and other air “purifiers” clear virus particles is disputed. They certainly can’t be relied on to do the job themselves.

Too many schools have spent Covid relief funds on such devices while neglecting other measures trib.al/r3TTvqC

Most classrooms are still poorly ventilated.

Stagnant air, thick with exhaled carbon dioxide, helps spread disease and hinders student performance trib.al/r3TTvqC

It takes power to move and filter air adequately — but Covid has shown that regulators need to face this trade-off.

States should require building operators to tell occupants how well their air is being ventilated trib.al/r3TTvqC

Two years ago, not many policy makers had “quality of building ventilation” on their list of priorities.

Score it as one more thing that needs to change trib.al/r3TTvqC