Breathing it in wont harm ya, but you'll definitely start to feel happier. More of that kind of state of mind where you acknowledge how happy you are, or finds good reasonings to work through rougher feelings if you were in that state before. I prefer to see it kinda like a layer on the current mood

Though I imagine a strong enough state of mind will make the fog harder to ignore or resist. I still imagine you keep your sense of control, say the moods angry and you just leave, then youll be unaffected. You got to stay in range to end up feeling these effects.