A chart that can be used to convert micron particle sizes into either a tensile bolt cloth or market grade mesh sizes can be found at the Powder Technology, Inc. website. The conversion chart also lists particle sizes in inches and provides relative U.S. standard sieve sizes with their opening sizes in inches.
Another conversion chart can be found at the Sigma Aldrich website and begins with standard and mesh sieve designations in millimeters and inches, respectively. The chart then provides the relative nominal sieve opening size in inches, millimeters and microns.
The micron is an International Bureau of Weights and Measurements unit of length which is equal to about 0.000039 inches, or more precisely, one thousandth of a millimeter. The diameter of a human hair is about 90 microns.