Maps show U.S. air quality and Canada wildfire smoke forecast

An air quality map shows conditions improving across the United States Friday as smoke from the Canadian wildfires subsides after prompting air quality alerts and advisories in several states this week.

The map shows unhealthy air primarily over Canada with much of the Midwest and Northeast facing mostly moderate air as of Friday morning, according to a federal measurement system called the Air Quality Index . Some parts of the U.S. could still face unhealthy air for sensitive groups.

The air index has six ratings:

Good

Moderate

Unhealthy for sensitive groups

Unhealthy

Very unhealthy

Hazardous

Sensitive groups include those who have a heart or lung disease, as well as older adults, children and pregnant women.

Multiple states, including Minnesota , Wisconsin, Illin