
Image caption
A highly magnified photo of soot particles illuminated with a laser. At just a few hundred nanometers in length (a single sheet of paper is about 100,000 nanometers thick), these particles can easily enter human airways. NASA image.
A highly magnified photo of soot particles illuminated with a laser. At just a few hundred nanometers in length (a single sheet of paper is about 100,000 nanometers thick), these particles can easily enter human airways. NASA image.