Typically used to refer to microplastics originally manufactured to be that size. Primary microplastics can include but are not limited to microbeads as they can also refer to industrial plastic powders and pellets. Source: UNEP (2018). Legal Limits on Single-Use Plastics and Microplastics: A Global Review of National Laws and Regulations. p. 5 adapted from IM0/ FAO/ UNESCO-IOC/ UNIDO/ WMO/ IAEA/UN/ UNEP. UNDPP Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) 2015.