Nitrous oxide ( n2o ) , a naturally occurring greenhouse gas , was one of the trace gases of nitrogen cycle . its lifetime was about 120 years in the troposphere . it has caused considerable concern since n2o not only contributed to the destruction of stratospheric ozone , but also its greenhouse effect strength was about 200 times higher than carbon dioxide ( co2 ) 溫室效應(yīng)氣體n _ 2o是氮素循環(huán)中的痕量氣體之一,其溫室效應(yīng)強度是co _ 2的200倍左右,它在大氣中的停留時間長達(dá)120年,而且,其消耗或轉(zhuǎn)化是以破壞o _ 3為代價的。