So there is a magic point, greater than zero, where it simply switches from healthy to unhealthy? That seems improbable.
Edit: Downvotes but no comments. That's a pretty low effort way of admitting your position is faith-based, not scientific.
Edit: Downvotes but no comments. That's a pretty low effort way of admitting your position is faith-based, not scientific.
If any of these measures is "in the red", your air is unhealthy.
Why not?
There are lots of people and groups out there for which this is the goal.