Tokyo Institute of Technology

About: Tokyo Institute of Technology is a education organization based out in Tokyo, Tôkyô, Japan. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 46775 authors who have published 101656 publications receiving 2357893 citations. The organization is also known as: Tokyo Tech & Tokodai.

Constraining the atmospheric N 2 O budget from intramolecular site preference in N 2 O isotopomers

Abstract: Nitrous oxide (N2O) is an important trace gas in the atmosphere. It is an active greenhouse gas in the troposphere and it also controls ozone concentration in the stratosphere through nitric oxide production1. One way to trace the geochemical cycle of N2O is by measuring the natural abundance of stable isotopes, namely 15N and 18O (refs 2,3,4,5,6,7,8,9,10,11, 12,13,14,15). Here we report the intramolecular distribution of 15N within the linear NNO molecule, determined by measuring molecular and fragment ions of N2O on a modified mass spectrometer. This revealed a preference for 15N at the central N position, or α-site, within N2O isotopomers (isotope-containing molecules). Moreover, this preference varied significantly throughout the atmosphere. In the troposphere, low α-site preference indicates local emission of N2O from soils and fossil-fuel combustion, each with distinct isotopomer signatures, which then mixes with background N2O. In the stratosphere, on the other hand, loss of N2O is observed as enhanced α-site preference for 15N, due to fractionation during ultraviolet photolysis of N2O. We have constructed an atmospheric mass balance of N2O, incorporating isotopomer abundance, which shows that the intramolecular distribution of 15N is a parameter that has the potential to increase significantly the resolution with which sources and sinks of N2O can be identified and quantified in the atmosphere.