6 July 2015
Several NASA satellites have sensors that can look at different wavelengths in the visible to infrared to sense things like dust and smoke. The image below is made up of two wavelengths around 500-550 nanometers in the visible light spectrum. Dust and smoke show up very well in this range. The red to the south is dust from the Sahara desert and the red across Canada and and the dark red barley visible over the Eastern U.S. is smoke from the wildfires in Alaska and Northern Canada. The hazy skies over southern Florida and into Texas today are courtesy of vast Sahara Desert thousands of miles away!
Another technique is to make what is called and RGB (for red green, and blue) image of different wavelengths. The image below shows the dust in orange and the smoke in green.