Worldwide (as of 2018) around 400 million tons of plastic are processed each year.
During and after the use of a plastic part, it can get fragmented due to different effects. From larger plastic parts, small pieces of plastic arise.
If the size of these particles is in between 5 millimeter and one micrometer (0,001 mm), the particles are called microplastic.
Continuing the decomposing process smaller parts arise.
If the size lies between one micrometer and 100 nanometer (0,0001 mm) they are called sub-microplastic.
Below a size of 100 nanometer the particles are called nano plastics.
In how far microplastics affect people and the environment is an important issue and is being intensively researched.