Smoke from several Canadian wildfires has drifted into the Bay Area, causing officials to warn of worsening air quality through Wednesday. The Bay Area Air Quality Management District has extended an air quality advisory first issued Monday,

The Bay Area Air District has extended an air quality advisory through Thursday because of wildfire smoke coming from Canada.

As air quality advisories continue to engulf the Midwest following Canada wildfires, hundreds of thousands of people in four states have been told to stay indoors.According to the EPA's (Environmental Protection Agency) AirNow map,