Agreed. In fact, even before COVID this was long overdue to be addressed in classrooms etc:

> ventilation to reduce rebreathing and CO2 levels

Unfortunately since that hasn't happened yet, methods like:

> In-line far UV sterilisation

> HEPA

are not effective. It isn't that they don't kill/stop the virus. The problem traces back to the inadequate forced air exchange and distribution which these methods require, and which is often a show stopper when you're talking about retrofitting existing structures without costs becoming insane. At a certain point it's easier to build new with these things in mind (and we absolutely should be taking requirements to do so more seriously).

> might not be enough as a single-building intervention, but it would almost definitely change disease spread dynamics if deployed world/nation wide.

The point of the previously linked study is to demonstrate that "something is better than nothing" reasoning doesn't always apply. We need to go big to see an actual measurable improvement over longer time spans. Otherwise, what's the benefit seen if you delay an average (but inevitable) infection from occurring by X days? There basically is none.