LOS ANGELES — A smoke advisory due to the wildfires in the Los Angeles area has been extended through at least 10 p.m. Sunday.

"Smoke from the multiple fires is expected to most heavily impact northwest coastal Los Angeles County including Pacific Palisades, the area of Altadena and Pasadena, near San Fernando, respectively, and areas near the fire," according to the Los Angeles County Department of Public Health.

Officials said wildfire smoke is a mixture of small particles, gases and water vapor. The primary health concern is the small particles, which can cause burning eyes, runny nose, scratchy throat, headaches and illness (i.e., bronchitis). Severe effects can include difficulty breathing, wheezing, coughing, fatigue, and/or chest pain.

"Predicting where ash or soot from a fire will travel, or how winds will impact air quality, is difficult, so it's important for everyone to stay aware of the air quality in your area, make plans, and take action to protect your health and your family's health," said Dr. Muntu Davis, health officer for Los Angeles County. "Smoke and ash can harm everyone, even those who are healthy. However, people at higher risk include children, older adults, pregnant individuals, and those with heart or lung conditions or weakened immune systems."

The health department urged people in areas where there is visible smoke or the smell of smoke or unhealthy air quality to avoid unnecessary outdoor exposure and limit physical exertion.

Pets can also be affected, the agency reported.

The South Coast Air Quality Management District also extended a ban on indoor and outdoor wood burning in much of the Southland due to a forecast of high air pollution in the area.

The residential wood-burning ban will be in effect until at least 11:59 p.m. Sunday for all those in the South Coast Air Basin, including the non- desert portions of Los Angeles, Riverside and San Bernardino counties, and all of Orange County.

The order does not apply to mountain communities above 3,000 feet, the Coachella Valley or the high desert, according to the South Coast Air Quality Management District. Homes that rely on wood as a sole source of heat, low-income households and those without natural gas service also are exempt from the requirement.

Residents in the affected areas are reminded that burning wood in their fireplaces or any indoor or outdoor wood-burning device is prohibited, as is burning manufactured fire logs, such as those made from wax or paper.

Fine particles in wood smoke, also known as particulate matter or PM2.5, can get deep into the lungs and cause respiratory problems such as asthma.

For real-time and forecasted air quality information, the AQMD Mobile App can be downloaded, information is also available online.