The Los Angeles Fire Department said that the smoke entering the L.A. basin, which could be widely seen across Southern California, "is from distant wildfires in North and Central California." The department added that residents should not call 911 to report the smoke.
The South Coast Air Quality Management District reminded residents to be aware of the air quality outdoors and issued a special air quality advisory in effect through Friday.
"While the heaviest smoke will be present in the upper atmosphere across the region, impacts on surface air quality are expected in the San Bernardino, San Gabriel, and San Jacinto mountains," the agency said, adding that the air quality index may reach unhealthy levels for sensitive groups.
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The AQMD advised residents to close windows and avoid any strenuous physical activity outdoors.
A brush fire erupted in San Bernardino Wednesday near the 215 Freeway, prompting evacuation orders, but firefighters quickly stopped its spread.
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DEVELOPING: We will add more details to this report as they become available.