Language Point 42

Many European countries and the United States check vehicles for gas and smoke emissions to make sure the levels are below the permitted output. (Para. 31)

Meaning: Many European countries and the United States carry out checks on automobiles to control the quantity of gas and smoke sent out from them and limit it to the permitted level.

emission: n. 1. something that is sent out 排放物

The city is polluted by the emissions from automobiles.

汽车的排放物污染了这座城市。

2. the act or the action of sending out something 排放

The emission of smoke and ashes is from that factory.

烟尘是从那个工厂排放出来的。

Please take care to note that the verb form of "emission" is "emit".

The machine emits clouds of gray smoke.

这台机器释放出灰色的烟雾。

The trunk of the rubber tree emits drops of liquid rubber.

橡胶树的树干流出一滴滴液状橡胶。

output: n. production

The factory used to have an output of 100,000 cars a year.

这家工厂过去每年生产10万辆汽车。