Wrangell Sentinel -

FAIRBANKS (AP) — In the pristine expanse of Alaska’s Interior lies a dirty secret: Some of the most polluted winter air in the United States can be found in and around Fairbanks.

The Fairbanks North Star Borough, which includes Alaska’s second-largest city, routinely exceeds limits set by the U.S. Environmental Protection Agency for particle pollution that can be inhaled and cause myriad health problems.

Over seven weeks this winter, nearly 50 scientists from the U.S. and Europe descended on Fairbanks to study the sources of air pollution, how the contaminants interact in the city’s...