Atmospheric N2O levels averaged 310 ppb (parts per billion) during 2021, or around 19 % greater than pre-industrial levels. It is a 300 times stronger greenhouse gas than CO2 by itself, because its absorption is not saturated in the atmosphere. When water vapor is dominant it is diminished by over 90% since it is at the edges of the Atmospheric window. On the other hand the lifetime of N20 in the atmosphere is short and is typically greatest at 5 p.m. One of the major reasons for the N2O increase is the increase of fertilization with nitrates, the other is from diesel fumes from trains, boats and trucks.
The picture shows a small N2O peak at 7.9 micron. This is because at lower wavelengths absorption from water vapor has nearly eliminated the N2O contribution. Remember that total absorption can never exceed 100 %, so the maximum absorption from N2O occurs at 8.1 micron, At 0.32 ppm it amounts to a greenhouse effect of 0.018 C. Before industrialization the N2O concentration was 0.27 ppm which results in an increase of the greenhouse effect of 0.0029 C from rising levels of N2O since before industrialization .
N2O is commonly called laughing gas, and is hazardous in high concentrations, and should be limited in confined places, but in concentrations of under 1 ppm nobody laughs.
Len Bilén's blog, a blog about faith, politics and the environment. 