Image from NASA's Ozone Measuring Instrument on the Aura satellite showing the levels of nitrogen dioxide of Ontario and the Great Lakes. The highest levels of nitrogen dioxide are shown in red. Image: NASA website.

Satellite images recently showed air pollution from Ontario fires in the Great Lakes region.

Nitrogen dioxide, which forms when nitrogen combines with oxygen during combustion, appears in NASA satellite images taken from July 15 to July 18.

The fires caused thousands of Canadian residents to evacuate.

The image was created with NASA’s Ozone Measuring Instrument. It measures the number of nitrogen dioxide molecules in a cubic centimeter.

The highest concentration was observed in the southern tip of Lake Michigan.

It prompted the Minnesota Pollution Control Agency to issue an air pollution alert, reported the Duluth News Tribune.