The hazardous air quality in Los Angeles is largely a result of smoke from the Pacific Palisades Fire, intensified by strong Santa Ana winds.

A law enforcement task force has been set up to uncover what caused the fires. The local agencies involved — the Los Angeles fire and police departments and the county Sheriff’s Department, as well as Cal Fire — are considered to be among the most skilled in the country. The Bureau of Alcohol, Tobacco, Firearms and Explosives is leading the probe.