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

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

Some areas near the border with Canada — including northern Minnesota, parts of Michigan and northern New York — were still facing unhealthy air on Friday afternoon, according to a federal measurement system called the Air Quality Index . Other areas of the Midwest and Northeast had ratings of good, moderate or unhealthy 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.