LOS ANGELES (CBSLA) — The South Coast Air Quality Management District has issued a smoke advisory due to the fires burning in Azusa and Castaic.

The advisory will be in effect throughout the afternoon Friday, and could be extended if the fires keep burning throughout the weekend.

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Several wildfires are sending heavy smoke into Southern California’s skies. The Lake Fire, which erupted Wednesday near Castaic, sent up a huge smoke plume that was visible across the region. Since then, brush fires have also broken out in Azusa and Corona.

The SCAQMD said that the air quality may be unhealthy for sensitive groups due to wind bringing smoke and ash from the Lake Fire into portions of the Santa Clarita Valley, and from the Ranch Fire in Azusa into the San Gabriel and Pomona-Walnut valleys.

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“The minute I walked into my office, I started getting phone calls, mostly from patients of mine who had underlying conditions like lung conditions, COPD, asthma and heart conditions,” Dr. Marina Manvelyan, an internist, said.

Manvelyan said the combination of particles in the air, thick smoke from the fires and extended elevated temperatures could cause irritation to airways — especially for those with sensitivities.

Anyone who sees or smells smoke should limit outdoor exposure by staying indoors with windows and doors closed and avoid vigorous physical activity.

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AQMD said winds were expected to shift this evening, blowing the smoke away from the region.