A particle size of 1 micrometer is equivalent to how many microns?

A particle size of 1 micrometer is equal to 1 micron because the terms "micrometer" and "micron" refer to the same measurement. Both are units used to express length in the metric system, specifically representing one-millionth of a meter. This equivalence means that when you have a particle size of 1 micrometer, it is precisely the same as saying it is 1 micron without any conversion necessary. The other options reflect incorrect conversions of measurement and do not accurately represent the definition of a micrometer or micron.