Air quality
Ever day driving home from work, I come over the crest of this one hill and look down on the valley where Yantai University is along with my apartment. Most days there is this huge cloud of haziness blanketing the entire area. 30 seconds later you can no longer see the cloud because you are actually in it... can't see the forest for the trees.
Anyway, healthwise I'm pretty sure that living in China for two years is the equivalent of chain smoking cigarettes for 6 months (two days ago was my two year mark in Yantai!).