Southern California pounded by smoke, unhealthful air from fires across the West Coast

A person walks across the 1st Street Bridge in downtown Los Angeles as smoke from nearby fires hovers in the sky Wednesday
A person walks across the 1st Street Bridge in downtown Los Angeles as a layer of smoke from nearby fires hovers in the sky on Wednesday.
(Gary Coronado / Los Angeles Times)

Southern California should prepare for another miserable air day.

The South Coast Air Quality Management District is warning that smoke and ash are likely to hit much of Los Angeles, Orange, Riverside and San Bernardino counties Thursday due to two major fires locally and smoke flowing in from Northern California blazes.

The air district’s smoke advisory said that most of the Southern California region will be affected by smoke, with the highest readings of fine-particle pollution, tiny lung-damaging particles known as PM2.5, in areas closest to the Bobcat and El Dorado fires.


Smoke blowing in from Northern California “may also contribute to widespread elevated PM2.5 concentrations,” the air district said, but due to shifting winds, the effects of the smoke “will be highly variable in both space and time.” The air district said to expect “noticeable smoke and ash impacts” in southwest Los Angeles County, Orange County and southwest Riverside County.

The Bobcat fire has been producing “substantial amounts of smoke” generating unhealthy air in Azusa, Glendora and other San Gabriel Valley communities while sending falling ash over much of the L.A. Basin. The smoke plume from the El Dorado fire, in San Bernardino County, is much smaller but is pushing air quality to unhealthy levels in the Redlands and Yucaipa areas.

The bad air is being generated by fires raging in California, Oregon and Washington that are lofting smoke into the air in a massive plume that is blanketing the entire West Coast and extends far out over the Pacific Ocean.

Air quality officials said the high pollution readings were a result of intense heat combined with stagnant weather conditions.

Sept. 10, 2020

In Southern California, much of that smoke has remained aloft. At ground level, air quality remained in the “good” to “moderate” range Thursday morning across most of the region, except for areas in near the Bobcat and El Dorado fires, where readings showed air quality in the “unhealthy” range.

Air quality has been significantly worse in Northern California, where raging fires this week have choked the air with smoke and ash and snuffed out the sunlight, casting a gloomy, orange pall over San Francisco and other areas. Air-monitoring data on Thursday morning showed unhealthy pollution levels in much of the San Francisco Bay Area.

In the Bay Area on Wednesday, a marine layer from the Pacific protected lower elevations from the oppressive, sun-smothering smoke, leaving the air tolerably breathable. But there were no views of the mountains from Mountain View. The skies darkened to a twilight-like dimness.


Street lamps along the peninsula’s El Camino Real illuminated the road for noontime traffic, while hotels and restaurants in Palo Alto and Mountain View kept their marquee lights and entrance displays on — lending a dinner-like atmosphere to their lunchtime patrons.

From Sacramento to the Bay Area to Monterey, motorists turned on their headlights to navigate the gloomy streets.

With so many fires burning, millions of people in the Bay Area, Central Valley and parts of Southern California are breathing dangerous levels of particle pollution.

Sept. 10, 2020