Longtime exposure to particulate matter especially the particulatematter smaller than 2.5 micrometers (PM2.5) which can go directly to thealveoli of the lungs is a major health hazard.

专家称，长时间呼吸空气中的颗粒物，特别是直径小于2.5微米的可入肺颗粒物（PM2.5）对人体健康危害很大。 。

youdao

PM2.5 is of especially great health concern because it can penetrate deep into the lungs, but the researchers lacked the data to analyze those tiny particles separately.

因为它可以渗透到肺部深处，PM 2.5引起人们对健康的极大担忧，但研究人员缺乏数据来单独分析这些微小颗粒的实际影响。

youdao

This can lead to fluid build-up in the lungs that causes difficulty breathing, or fluid retention in other parts of the body (especially the legs) that causes swelling.

血流聚集在肺部的话，就有可能引起呼吸困难；血液聚集在身体的其他部分，尤其是腿部的话，则可引起水肿。

youdao