Southern California air quality advisory

South Coast Air Quality Management District extended a wildfire smoke advisory through 10 p.m. Thursday after several fires sent smoke across much of Southern California. The agency said the advisory covered Los Angeles, Ventura, Riverside and San Bernardino counties, with impacts stretching from inland communities to coastal areas. Smoke from the Sandy Fire in Simi Valley and the Bain and Verona fires in Riverside County was a main driver of the alert, while smoke from the Santa Rosa Island Fire also moved onshore into parts of the region. Health officials urged people in smoke-affected areas to stay indoors and limit exertion. ### Which fires were driving the advisory? The Sandy Fire in Simi Valley, the Bain Fire in Jurupa Valley and the Verona Fire in Homeland were among the main sources cited by South Coast AQMD and local broadcasters in the advisory area. FOX 11 reported that the Sandy Fire had prompted evacuation orders and warnings in Ventura and Los Angeles counties, while the Bain and Verona fires had also led to evacuation activity in Riverside County. A May 19 South Coast AQMD advisory update said the Verona Fire had burned 600 acres in Riverside County and the Bain Fire 1,375 acres, while the Sandy Fire had burned 1,698 acres near Simi Valley at that time. The agency said conditions could change quickly because of fire activity and weather. ### How wide was the air quality alert? South Coast AQMD said the smoke advisory applied to Los Angeles, Ventura, Riverside and San Bernardino counties and remained in effect until 10 p.m. (foxla.com) Thursday. NBC Los Angeles reported the extension covered a broad swath of Southern California, and the agency’s advisory page listed the alert as valid from Wednesday, May 20, 2026, until Thursday, May 21, 2026, at 10 p.m. (aqmd.gov) NBC Los Angeles said “widespread moderate smoke impacts” were expected across the Los Angeles Basin, Catalina Island, the Inland Empire and the Coachella Valley. FOX 11 reported conditions had deteriorated from the Inland Empire to the coast. ### What did officials say residents should do? Scott Epstein of South Coast AQMD told FOX 11 that people in smoke-polluted areas should remain inside and keep windows and doors closed. (foxla.com) He also said residents should limit outdoor exercise or exertion because heavier breathing increases pollution exposure. South Coast AQMD said people in smoke-affected areas should avoid vigorous physical activity, use air conditioning or an air purifier if available, and avoid bringing outside air indoors with swamp coolers or whole-house fans. (nbclosangeles.com) The agency also said anyone who had to be outside could use a properly fitted N95 or P100 respirator for some protection. ### Why were smoke impacts lingering across the region? (foxla.com) Weak winds were forecast over the coming days, limiting smoke dispersion out of the region, according to FOX 11 and NBC Los Angeles. South Coast AQMD said on May 19 that smoke impacts had lingered in part because light winds allowed pollution to build up. South Coast AQMD said smoke from the Santa Rosa Island Fire that had moved over the ocean was expected to come ashore and affect the coastline of Los Angeles and Orange counties, while areas near the Sandy Fire could reach the unhealthy-for-sensitive-groups category or higher. (aqmd.gov) The agency said parts of Riverside and San Bernardino counties near the Bain and Verona fires could also reach that category or worse. (foxla.com) ### Where could residents track conditions next? South Coast AQMD said residents could use its AQI map and mobile app to check current neighborhood air quality as conditions changed. The agency’s air advisory page said smoke advisories are issued for large fires in or near its jurisdiction and advised people to avoid or limit outdoor activity if they smell smoke or see ash, even outside formally listed impact areas. (aqmd.gov) The advisory was set to run until 10 p.m. Thursday, May 21, 2026, and South Coast AQMD said it would issue updates if additional information became available. (xappp.aqmd.gov) (aqmd.gov)