Breathing dangerously: Wildfires blanket LA in hazardous smoke

The U.S. city of Los Angeles (LA) choked under a thick blanket of smoke Thursday as wildfires raged across Southern California, forcing schools to close and prompting health warnings as residents struggled to breathe.

"It's not breathable," Dulce Perez, a cook at Teddy's Cocina in Pasadena, told Reuters. "We just try to stay indoors."

All around the United States' second-largest city, residents worried about air that has, at times, turned lung-burning from the ash, soot and smoke emanating from fires that have destroyed 10,000 structures.

Air purifiers were sold out at some big-box stores, according to interviews with employees at four businesses. Some residents were taping windows to keep the smoke out of their homes.

Firefighters finally started gaining control over two major wildfires on the eastern and western banks of LA on Friday as fierce winds that supercharged the fires for days finally eased.

While conditions improved on Friday, an air quality alert remained in effect until the evening and dangerous particulate matter remained around four times World Health Organization guidelines.

Potential impact on health

Fanned by fierce winds and fueled by vegetation bone-dry after a long period of little or no rain, the LA fires broke out on Tuesday and have relentlessly burned more than 137 square kilometers. Neighborhoods have turned to ash in some parts of LA.

Wildfire smoke typically carries with it noxious gases and particulate matter that make it more toxic than normal air pollution. Not only does wildfire burn plants, brush and trees, but also buildings, houses and cars that contain plastics, fuels, metals and a host of chemicals.

Studies have linked wildfire smoke with higher rates of heart attacks, strokes, and cardiac arrests as well as weakened immune defenses.

"The levels of wildfire smoke we've seen in LA these past few days imply between a 5 to 15 percent increase in daily mortality," said Carlos Gould, an environmental health scientist at the University of California San Diego.

(With input from agencies.)