*2.1. Distribution Profile*

At present, the relevant studies on the distribution of MPs mainly pay attention to the water and soil environment and the number of studies about atmospheric MPs is limited (Table 1). The earliest research on the distribution of atmospheric MPs can be traced back to Dris et al. collected and analyzed samples of outdoor air in Paris's urban areas, where the concentration of MPs ranged between 29 and 280 items/m2/day. The size of MPs ranged from 0.1 to 5 mm, and the shapes mainly included fibers and fragments [30]. In another study, Dris et al. measured that the number of MPs in indoor air in Paris reached 5.4 items/m3, while that in outdoor air in the same area was only 0.9 item/m3, indicating indoor human activities among the major sources of MPs in indoor settings [31].


**Table 1.** Distribution and abundance of plastics in the atmosphere.


**Table 1.** *Cont.*

available.

Subsequently, studies on atmospheric MPs have been carried out around the world, including a dozen countries and regions in Asia [33,34,38,39,47], Europe [36,43,45], and the Arctic [48]. The survey areas include urban sites, such as municipal areas [38], apartments [31], offices [31], industrial areas [40], terminals [35], and universities [47], as well as suburbs [32], rural areas [27], mountains [42], straits [46], estuaries [46], oceans [41,46], glaciers [28], and even the planetary boundary layer (PBL) [27]. These studies sugges<sup>t</sup> that MPs exist in the atmosphere worldwide, from near the ground level up to 1.5 km high.
