ozone
/ˈoʊˌzoʊn/
a colorless gas (O3) soluble in alkalis and cold water; a strong oxidizing agent; can be produced by electric discharge in oxygen or by the action of ultraviolet radiation on oxygen in the stratosphere (where it acts as a screen for ultraviolet radiation)
中文释义：臭氧
The ozone layer in the stratosphere protects Earth from harmful ultraviolet radiation.
平流层中的臭氧层保护地球免受有害紫外线辐射。
Ground-level ozone is a major component of smog and can cause respiratory problems.
地面臭氧是烟雾的主要成分，可能导致呼吸问题。