Although today will technically feature sunny skies, it will look very grey due to hazy wildfire smoke pushing in from Canada. Daytime heating will cause the air to mix and more smoke to be brought down to the surface,

The advisory now runs through the late afternoon on Saturday, with expected air quality rated from moderate (yellow) to unhealthy (red).

Smoke from Canadian wildfires is once again impacting Chicago’s air quality, with air quality index readings Thursday morning in the “unhealthy” category for some, according to government air quality website AirNow.