A fire marshal, in the United States and Canada, is often a member of a fire department but may be part of a building department or a separate department altogether.
An average human red blood cell is approximately 5 microns in diameter. The average diameter of human hair is roughly 0.0035 inches in diameter, which is equivalent to 75 microns. The abbreviation micron was initially used to distinguish the units of a tool used to measure small distances, also called a micrometer.
How big is a Micron? A micrometer, commonly known as micron is one millionth of a meter, one thousandth of a millimeter or one thousand nanometers. A strand of human hair is about 100 microns wide and a red blood cell is approx. 8 microns in diameter.The illustration below is 2,000 times larger than actual size.