By The Associated Press
2:59 PM AKST, December 21, 2012
Fairbanks area residents are again being warned about breathing the air.
The Fairbanks Daily News-Miner says wintertime air pollution has returned to the Fairbanks area because of lower temperatures and a strong inversion.
Temperatures on Thursday reached 40 degrees below zero at the Fairbanks International Airport.
That prompted the North Star Borough to post advisories with an "unhealthy" rating for Fairbanks and a "very unhealthy" rating for the North Pole area. Borough Air Quality Division technician Jim McCormick said the inversion, which traps air pollution, said it's expected to stay at least through the weekend.
Residents are being warned against prolonged outdoor exertion for people with heart or lung disease, the elderly and children. Those people also should avoid any outdoor activity in North Pole.