LOS ANGELES, Jan. 21 (Xinhua) -- Millions of Southern Californian residents have been advised to limit outdoor activities due to bad air quality amid devastating wildfires, according to the U.S. National Weather Service (NWS).

The NWS has issued several air quality alerts covering the South Coast Air Basin, Coachella Valley and eastern Riverside County.

Very strong Santa Ana winds and extreme fire weather have been forecasted for portions of Los Angeles and Ventura counties starting Monday.

Stronger and more widespread Santa Ana winds are expected overnight to the typical wind-prone areas of Los Angeles and Ventura counties, according to the NWS Los Angeles.

The South Coast Air Quality Management District has issued a windblown dust and ash advisory due to strong Santa Ana winds expected throughout the region through Tuesday evening.

The NWS has issued Red Flag Warnings, High Wind Warnings, and Wind Advisories for much of the area. ■