¹⁵N/¹⁴N ratios of NO>_x from vehicle engines and coal-fired power stations

Abstract

Preliminary data are presented for the ¹⁵N/¹⁴N ratios of the two main sources of anthropogenic NO_x. Contrary to expectation, the δ15N values of NO_x emitted from vehicle exhausts (- 13 to -2‰) and coal-fired boilers (+ 6 to + 13‰) are different from isotopic composition of the nitrogen in their fuel + air mixtures (- 0‰). These differences may reflect variable effects of kinetic isotopic fractionation in the formation (vehicles) and destruction (boilers) of NO, and have important consequences for the use of nitrogen isotopes in atmospheric studies.