The smoke was expected to most heavily affect northwest coastal LA County, and in areas nearest the Palisades, Eaton and Hurst wildfires.

The wildfires burning across LA are also degrading the air quality across the region. The resulting air pollution is a serious health threat, especially for children, pregnant people, older adults, and those with preexisting conditions.

Winds have begun shifting to the east, which drove the Eaton fire toward Arcadia and Monrovia early Wednesday morning. Smoke will more likely begin to blow into the eastern San Gabriel Valley, not as much to the south of the fire, Lyou explained. “Arcadia, Duarte and Azusa may see elevated levels (of bad air) from that fire,” he said.

On Wednesday at 12:26 p.m. an air quality alert was issued valid until Friday at midnight. The alert is for San Bernardino and Riverside County Valleys-The Inland Empire, Riverside County Mountains, San Gorgonio Pass Near Banning,

Southern California ‒ with sprawling cities, clogged freeways and heavy industry ‒ is already notorious for some of the worst air quality in the nation. This week's wildfires are putting millions of people at risk for immediate health problems and longer-term issues.

By Alison Withers, Dawn Chmielewski, Andrew Hay and Hannah Lang LOS ANGELES (Reuters) - Business was brisk at Teddy's Cocina in Pasadena as wildfire evacuees ate lunch and passersby ducked indoors to escape from the brown,

Incinerating commercial and residential buildings releases hazardous chemicals and gases from their materials.

As thousands of buildings burned in Los Angeles County this week, the skies above Southern California have become a stew of unhealthy gases and aerosols – much different than what typically blows from a wildfire.