Am I the only one who gets jumpy about ventilation when working with certain glass colors?
In my experience, some color rods can put off nasty fumes if your space isn't aired out. Take this with a grain of salt, but it's worth checking your setup before you begin a long session.
You're right that warmer air affects fumes, but it's not just about spreading. Warm air rises, so fumes will move upward more quickly. In a cold room, they might hang around near the ground. So, ventilation needs to account for that temperature difference.