1、The NOx emission is high along with the great of primary air rate.
一次風率越大，氮氧化物排放量越大。

2、Exhaust emission of vehicle engines is one of the primary air pollution sources.
車用內(nèi)燃機的廢氣排放是大氣污染的主要污染源之一。

3、Meanwhile, the control of air flow, furnace negative pressure and primary air flow are introduced.
同時也介紹了送風量、爐膛負壓和一次風量的控制。

primary air翻譯