SACRAMENTO, California (AP) -- Hundreds of lightning-sparked wildfires have turned the air of Northern California into an unhealthy stew of smoke and ash, forcing the cancellation of athletic events and other outdoor activities.
A satellite image taken Thursday shows most of Northern California obscured by wildfire smoke and ash.
A satellite image taken Thursday shows most of Northern California obscured by wildfire smoke and ash. Health advisories urging residents to stay indoors to limit exposure to the smokey air were issued Saturday from Bakersfield north to Redding, a distance of nearly 450 miles.
Air pollution readings in the region are two to 10 times the federal standard for clean air, Dimitri Stanich, spokesman for the California Air Resources Board, said Saturday.
Some areas are experiencing the worst air quality on record, with the smoke hanging down to the ground like a fog.
Air quality agencies are especially concerned about high readings of small-particle pollution. The tiniest particles can penetrate past the body's immune defenses, traveling deep into the lungs and the bloodstream.
"When you have it on the scale we are seeing now, it is very dangerous to the general public health," Stanich said. "This is a very serious problem."
Changing weather brought smoke-clearing breezes and brief relief to some areas Saturday, but it could also bring lightning storms similar to the ones that ignited fires across Northern California a week ago.
Thunderstorms could strike anywhere in the northern Sierra Nevada or the northern Central Valley on Saturday night, said National Weather Service forecaster Johnnie Powell in Sacramento.