"You are looking at the one--and only--non-smoking restaurant in the city"

What a load of crap.

Let's name some non-smoking restaurants in Beijing, then.

First, the vegetarian restaurants. All that I've been to are non-smoking. Is that a general rule without exceptions?

There are a few non-veg restaurants I know with substantial non-smoking areas (like Qin Tang Fu, the Shaani noodle joint). What else? (not counting Starbucks cafes).

The "Big Pizza" chain of buffet restaurants has always been non-smoking.
If you are a foreigner then most local Chinese will extinguish their tobacco torch when asked to do so in a designated non-smoking area.