Appears to be true:

> CO2 monitoring equipment should be provided in the apartment expected to be the main or principal bedroom in a dwelling where infiltrating air rates are less than 15m3/hr/m2 @ 50 Pa.

https://www.gov.scot/publications/building-standards-2017-do...

Well done, Scotland.

Monitoring equipment alone isn't really sufficient, unless it is hooked up to a fan or ventilation equipment to maintain a suitable level, and an alarm to alert if that level can't be maintained.

If the law requires just monitoring equipment, then you know that in a utility cabinet somewhere will be a screen with the data on, that nobody ever looks at, and might as well not be there.