Fig. 3. Boundaries of microplastic regulation.

Bans on primary microplastics are in place or imminent across many jurisdictions, aiming to stop pollution from targeted environmental applications, from particles that are lost through consumption or targeted environmental applications (green and blue hexagons). Some industrial intermediates (gray hexagons) may contain microplastics, but these particle forms vanish through further processing or product use. Labeling and reporting requirements on intermediates may be motivation for the development of label-free alternatives, if the regulatory definitions are precise and enforceable. Microplastic regulations do not aim to resolve the dominant sources of microplastic pollution, which instead require interventions through waste management or product reformulation (red, yellow and orange hexagons). Note hexagon coloring is linked to environmental microplastic sources in Fig. 2.