Wind whips trees as firefighters battle the Saddleridge fire in Porter Ranch, Calif., on Friday, Oct. 11, 2019. (Noah Berger/AP)

As multiple fires continue to burn across Southern California, representatives from the South Coast Air Quality Management District are urging residents to protect themselves from unhealthy air conditions, including heavy smoke and PM2.5.

PM2.5 refers to particle pollution, which the Environmental Protection Agency describes as "fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller."

"The biggest concern that we have during a wildfire is PM2.5," said Nahal Mogharabi, the director of communications at AQMD'. "For the L.A. area, we are seeing some elevated levels in portions of the San Fernando Valley and Malibu."

Particle pollution includes solid and liquid particulates in the air that can be inhaled, getting into the lungs and the bloodstream. Exposure to PM2.5 can result in health problems, largely affecting the heart and respiratory systems.

In L.A. County, where the Saddleridge Fire has burned thousands of acres, Mogharabi said that the San Fernando Valley, Santa Clarita, the Northwest coastal areas and the San Gabriel Mountain area are all experiencing bad air quality.

In Riverside County, the metro area as well as Perris Valley, San Jacinto Valley and the San Gorgonio Pass are experiencing bad air quality as a result of the Sandalwood, Reche and Wolf Fires.

A smoke advisory has been issued in those areas. Mogharabi said that the best way for residents and visitors to protect themselves is to stay inside.

"Overall, our general message that we like to get out there during a wildfire is, if you see smoke or see ash due to the fire, we recommend that you remain indoors with windows and doors closed, or seek alternate shelter," she said.

That is, of course, unless you are asked to evacuate.

AQMD also released an app that's updated every hour with real time information about air quality, and is available for download for iPhone and Android. The department also offers an interactive map with real time conditions.

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Correction: A previous version of this story misquoted Nahal Mogharabi as saying that residents in areas with bad air quality should stay inside with their windows and doors locked. She said residents should stay inside with their windows and doors closed. LAist regrets the error.