Smoke from a pair of Central California forest fires burning for more than two weeks in the heart of giant sequoia country continued to dim Southern California skies Monday.
The heavy smoke first wafted down to Southern California on Thursday and could remain a problem later this week, the South Coast Air Quality Management District said in a special advisory for Monday.
Smoke across the region will be the thickest in the upper atmosphere, but it’s expected to impact surface air quality in the San Bernardino and San Gabriel mountains.
Air quality was forecast to deteriorate Monday morning into the afternoon in the mountain areas, although levels had been measured at good or moderate throughout the region Sunday afternoon, the AQMD said.
The smoke was expected to push levels to unhealthy for sensitive groups or higher by Monday afternoon in the San Gabriel Mountains, and western and central San Bernardino Mountains.
Ozone levels not related to the smoke also could reach unhealthy for sensitive groups levels or higher in the San Bernardino Mountains Monday afternoon, officials said.
Sequoia National Forest and National Park remain closed as the fight against the fires continues in the Sierra Nevada.
More than 1,800 firefighters are battling the KNP Complex Fires, which covered more than 73 square miles with 8% containment by Monday.
Nearby, the Windy Fire grew significantly over the weekend. The blaze ignited by lightning on Sept. 9 has scorched 133 square miles of trees and brush on the Tule River Indian Reservation and in Sequoia National Forest. Containment shrunk from 5% to 2% Sunday, and remained at 2% Monday.
Meanwhile, the gusty northwest winds that have been pushing the smoke into Southern California are forecast to remain over parts of Los Angeles County through Tuesday, according to the National Weather Service.
Inhaling fine particulate matter in wildfire smoke can cause a variety of negative cardiovascular and respiratory health impacts, including heart attacks, asthma aggravation, decreased lung function and difficult breathing. It may even lead to an early death for those with heart or lung disease, officials said.
People in affected areas can help keep their indoor air clean by closing all windows and doors and running an air conditioner or purifier. They should avoid using any coolers that bring in outside air, like whole-house fans or swamp coolers, as well as pan-frying, grilling, and burning wood or candles.