Pollen grains are approximately 70 microns in diameter. The pollens are spherical with approximately 188 microns diameter. Pollens are circular with approximately 8 microns diameter. These filaments are then stretched and elongated until the average thickness is around 20 microns. Pollen is about 34 microns in diameter. PM 2.5 is a measurement of particulates in the atmosphere smaller than 2.5 microns. The implant consists of 60 electrodes, each 200 microns in diameter. Promyelocytes measure 12-20 microns in diameter. HEPA filters are also used to collect airborne pathogens larger than 0.3 microns. Pollens are round, roughly 65 microns in diameter. Lining thickness varies widely by maker, but averages between 7 and 10 microns. A human rod cell is about 2 microns in diameter and 100 microns long. For comparisons sake, a human hair is about 50 to 150 microns in diameter. IRAC is capable of observing in the wavelengths of 3.6, 4.5, 5.8, and 8.0 microns. Pollen grains are elongated, approximately 52 microns in size.