Air tainted with soot lingers in Bay Area (w/video)

SAN FRANCISCO — A stubborn dry weather pattern settled over Northern California in January, helping create some of the sootiest air in years for the 7.5 million people in the San Francisco Bay Area, air quality officials said Tuesday.

The Bay Area Air Quality Management District issued its 11th-straight "Spare the Air" warning on Monday, forbidding most indoor and outdoor wood burning.

The declaration tied last year's record for the most consecutive days of warnings involving unhealthy levels of airborne particulates.

Pollution levels exceeded the federal maximum-allowable levels on three of those days, air-quality district spokeswoman Lisa Fasano said.

"In the winter times, we get periods where we get an inversion layer that comes and hangs over the region and caps all the polluted air," Fasano said.

She said 11 days is long but not unprecedented for such inversions.

Much of California experienced one of the wettest Decembers in years, raising hopes that the three-year drought was easing.

In January, however, a pattern of high-pressure ridges blocked more wet storms from moving in, said forecaster Drew Peterson of the National Weather Service.

The same kind of pattern settled in last year, also after a comparatively wet December.

"The thing that's troubling is for the most part, this is typically one of the wetter months," Peterson said.

A weak storm system approaching the region was expected to slip to the north of San Francisco without bringing much rain.

The high-pressure ridge will likely settle back over the area next week, Peterson said.