Smoke from fires burning in Northern California is being blown into the Mid-Valley, prompting the Feather River Air Quality Management District to issue an air quality advisory for Yuba and Sutter counties.

"It's not very good right now," David Valler, the district's air pollution control officer said on Monday.

Smoke started to build up locally late Sunday evening, he said. The district's measure sensor on Almond Street in Yuba City indicated this morning that air quality is still good, but Valler said more smoke came into the valley as the day went on.

Fires are currently burning in many directions around the Mid-Valley, including in Nevada, Placer, Butte, Tehama, Shasta, Solano and Napa counties. All these fires could be contributing to local smoke because the area is "kind of in a vortex," Valler said.

"Obviously, there's a lot of smoke out there," he said.

Colusa County also announced an air-quality warning. A 4 p.m. advisory from the county Department of Health and Human Services urges residents — especially those with lung problems – to stay indoors due to soot and ash from fires in Butte and Tehama counties.

Harry A. Krug, director of the county's Air Pollution Control District, advised residents to follow the same precautions announced in the Yuba-Sutter area.

The Feather River district is recommending children and elderly residents keep outdoor activities to a minimal, and healthy residents should delay strenuous exercise, particularly if they can smell smoke in the air. Using paper masks is not recommended; they do not filter small particulate material in smoky air and restrict breathing.

Those with health problems, particularly respiratory problems, should remain indoors. Asthmatics should follow asthma management plans. Drinking water to keep airways moist is recommended. If people start experiencing chest pain, chest tightness, shortness of breath or severe fatigue, they should contact their doctor.

Valler said the advisories are usually issued on a day-to-day basis, unless containment on a fire is not expected for an extended period of time.

"It's difficult to forecast forest fires," he said.

Contact Appeal-Democrat reporter Robert LaHue at 749-4713 or rlahue@appealdemocrat.com. Appeal-Democrat reporter Howard Yune contributed to this report.