The smoke that has made a thick haze the last few days in San Andreas and elsewhere in Northern California is coming from distant wildfires, according to Brian Moss, the air pollution control officer for the Calaveras County Air Pollution Control District. Moss said in an email some of the smoke may even be coming from fires in Oregon, but the prime source is probably the Aspen Fire in the Sierra National Forest to the south.
According to federal fire incident data posted Tuesday, that fire is now about 14,000 acres and 20 percent contained. It was started July 22 by lightning.
There is some hope that low pressure moving inland later in the week, probably by Thursday according to the U.S. Weather Service, may get the air moving and offer some temporary relief. High pressure and the resulting stagnant pools of polluted air in the Valley and foothills are forecast to resume by the weekend.