Adam Goldstein was checking the Beijing air quality index on his iPad and laptop all day Saturday.

For once, though, he was hoping the index would show heavy pollution, since it meant cheaper beer. One of Beijing's micro-brew companies, Jing-A Brewing, was rolling out its latest brew, an IPA called the Airpocalypse, the price of which would be based on the amount of fine particulates in Beijing's air. If the AQI hit 500 or above, a measurement identified on the U.S. Embassy's Beijing Air Twitter feed as "beyond index,"...