Another day of smoke-filled skies is prompting air quality officials to extend a health advisory for the Bay Area.

Officials with the Bay Area Air Quality Management District say because of smoke from wildfires burning in the region, the air throughout much of the nine counties in the Bay Area region is expected to reach unhealthy levels again Friday.

With air quality gauges recording elevated levels of particulate matter, officials are advising people to take steps to reduce their exposure, including limiting outdoor activities.

People with asthma or lung disease are advised to follow their doctor's directions.

Elderly people and children are also considered susceptible to elevated air pollution levels.

The National Weather Service is predicting widespread haze and smoke will remain in the skies through at least Saturday night.

Meanwhile, a section of Highway 1 through the Big Sur coastline remains closed Friday morning as fire crews continue to battle a wildfire outside the town of Big Sur.

Since it was reported nearly a week ago, the fire being called the "Basin Complex" fire has burned about 42 square miles.

The more than 700 firefighters on the scene have been trying to strengthen their lines near populated areas, but are letting the fire burn through the steep mountain forests in the region.

Fire officials say with the fire only three percent contained, they can't provide an estimate when fire crews will be able to contain the blaze.

The fire has destroyed 16 homes, and is threatening nearly 600 more.

About 20 miles east of Big Sur another wildfire continues to burn.

The fire called the "Indians Fire" is 71 percent contained after consuming more than 92 square miles.

The continuing fires are destroying natural habitats of some animals and birds, forcing them to flee and seek shelter elsewhere.

The fires are also producing large amounts of pollutants and greenhouse gases that may pose long-term environment and health hazards.