That article's message is spot on.
If your CO2 levels are that high then you should fix the HVAC system and get it up to code or lobby for fixing the code. In many countries, a full air exchange in any office space every X hours is mandatory. In other countries that's optional and they need to get their act together.
Or just open the window for the world that doesn't have HVAC
In most of the world outside of the US, having "an HVAC system" is extremely rare.