So I've been accepted by a few different programs some of which have a variety of options for where to teach. My hesitation is the year commitment in a city I've never visited (travelled Europe only). I'm a single guy, not wealthy and I live a modest lifestyle. I've slight concerns about air quality and health factors (I enjoy the outdoors, running, tai chi, yoga). Shanghai looks attractive and exciting, though the size might be overwhelming for a year stay. What are good alternative with out sacrificing a quality experience? It'd be excellent to live in clean(er) air and close to outdoor adventure and some nightlife. Does that exist??

To make my decision more difficult, there's options for me in Taiwan, Thailand and Japan. Suggestions on how to narrow it down?