The American Lung Association has released State of the Air 2013, a report on air quality across the nation. The Anchorage Daily News has a nice summary of the situation, which is basically that Anchorage is doing well and Fairbanks is not, mostly due to wood burning for heat in the winter:
"Fairbanks is the 11th-most polluted city for short-term particle pollution and tied as the 18th-most polluted city in the nation for year-round levels of particle pollution. Particle pollution levels can spike dangerously for hours to weeks on end (short-term) or remain at unhealthy levels on average every day (year-round). On a positive note, Anchorage ranked as the 14th cleanest city in the nation with an annual particle pollution level of 6.2 µg/m3."