微粒

wēi lì wū rǎn wù zhì

微粒污染物质

particulate pollutant

fěn chén wēi lì

粉尘微粒

microscopic particles of dust

zhè xiē wēi lì tài xiǎo le jī hū kàn bù jiàn

这些微粒太小了，几乎看不见。

The particles are so small as to be almost invisible.

xiōng xiàn wēi lì

胸腺微粒

thymic corpuscle