二氧化碳排放量将减少20%。

Carbon dioxide ___emissions will be reduced by 20%.

最近的研究表明，来自交通的二氧化碳排放是空气污染的主要原因。

Recent studies show that CO2 ___emissions from traffic are a major cause of air pollution.

必须控制有害气体的排放以保护环境。

The ___emission of harmful gases must be controlled to protect the environment.