Importance or air intake/outake

Hello,

I have a questions. How important would you say it is to change the air in the growing room, especially for seedlings? Could stagnant air affect the time in which seedlings grow, maybe even stun them?

No fresh air is very bad. The seeds would probably pop but then wouldn't grow very well at all.

Extremely important

You want some air exchange for sure. Doesn't need to be a lot IMO. More critical at higher temperatures.

If you are running ANY ventilation to control heat or humidity you are getting plenty of air (probably)

As you get packed in toward the end of flowering you need more airflow as you have more vegetation transpiring, and more leaf surface to keep dry.

fresh air is a must, absolutely, but.... seedlings don't go through a lot of co2 so... it would depend on how many seedlings you have and size of the space they are starting out in...

How happy would you be if you had no air intake? Would you feel stunted?