The U.S. Embassy in Beijing publishes AQI values for Beijing and other cities in China, and the Chinese Ministry of Environmental Protection provides its own air quality data for cities throughout the country.

FORBES: Air Quality In China

During a call the service monitors how fast data are going through the air and adjusts call quality so the video doesn't cut off when a network's load changes or someone roams to a new cellular tower.

FORBES: Focus

Federal agencies collect enormous amounts of data about such diverse matters as automobile safety, air travel, air quality, workplace safety, drug safety, nutrition, crime, obesity, the employment market, and health care.

WHITEHOUSE: Share This Post

All told, we delved into more than a dozen data sources in order to assemble city rankings in 38 different criteria, including everything from air quality to unemployment, cost of living to death rates.

MSN: You'll never guess the healthiest U.S. city for guys - Health | NBC News