Table 2 The physical properties of AMNPs

Size

15–250 μm

①Smaller particles generally pose a greater toxicity risk.

②The density and aerodynamic characteristics of atmospheric MPs are connected to their size dispersion.

[53, 54]

Color

Red, white, black and yellow

①Color assessment can be influenced by experimenter bias.

②Color can serve as a useful parameter to assist in identifying potential sources and associated surface contaminants related to AMNPs.

[56, 57]

Shape

Spheres, fibers, films, and pieces

①Offers crucial hints on the source and polymer makeup.

②The original shape of AMNPs is affected by aging processes, residence duration in the environment, and decrease of surface performance.

③Fibrous particles and their bending stiffness can increase the toxicity of AMNPs.

[59, 63, 64]

Potential

ζ-potential

①Depends on their surface charge.

②Involve in the cytotoxicity of AMNPs.

[65, 66]