Skylab was the first U. S. space station, and the astronauts would need to know if a fire had started or if noxious gases were loose in the vehicle.

Skylab是美国第一个空间实验室，当火灾发生时或者有害气体发生泄漏时，宇航员需要立刻做出反应。

youdao

So too are many of the factory chimneys that help turn the city's rarefied air into noxious smog.

ECONOMIST: Mexico

Seoul's air, once famously noxious, is much improved, but South Korea lags at conservation.

ECONOMIST: What Lee Myung-bak still needs to do