Heavy smoke has been present near the fires for weeks, but many areas have avoided poor air quality until recently.
Smoke and haze moved south into the Tahoe basin from the Tamarack Fire earlier in the week, but a wind shift helped clear the area.
That same pattern shift is bringing north wind to valley locations and is spreading smoke and haze to more areas in Northern California.
The Dixie Fire has burned more than 200,000 acres so far and is one of the 15 largest in state history.
Most of the smoke and haze from that fire moved North out of the state, but winds are changing. Smoke has funneled down the Feather River Canyon and moved into the Sacramento Valley.
Stronger north winds will spread smoke to areas south of the fire like Oroville, Yuba City, Davis and Sacramento. Spare the Air is detecting unhealthy levels of smoke north of Sacramento and the private company Purple Air is detecting unhealthy levels of smoke in the Sacramento area.
This pattern of wind is part of a heatwave that will bring valley temperatures above 100 degrees Wednesday and for the rest of the week.
Anyone that is sensitive to smoke is advised to limit outdoor activities and remain indoors if possible. Poor air quality is possible the rest of the week.
WATCH MORE FROM ABC10: California Wildfires: Dixie Fire nears 200,000 acres