There is this forest in my world with the vegetation feeding off the humidity of the air. Because the plants keep draining humidity, the air becomes dry -- near 0% of humidity. Precipitation happens, and rivers flow throughout the forest, therefore it is not that hard to find water to survive. Plenty of berry bushes, mushrooms, and fruit trees populate the area, making it rich in food for herbivores. But the air is void of water. The air is harsher than a desert in nature.
Basically, this is a normal forest with no humidity in the air. I know that 100% humidity is extremely harsh on humans because they can't regulate temperature, but I have no idea of the consequence of 0% humidity. So, I was asking myself:
Can humans or other animals even breathe air that dry? For a limited/extended period of time? What sorts of effect would it have on their bodies?
Essentially: What are the consequences of living in an area with VERY dry air?