Eddy-covariance measurements of nitrous oxide fluxes above a city

Direct measurements of urban N(2)O emissions were made for the first time using the eddy-covariance technique from a tower, approximately 65 m above the street level of Edinburgh (Scotland, UK) during November 2005. The measured N(2)O concentrations had a median value of 358 ppbV and the overall mean measured flux was 91 ng N(2)O-N m(-2) s(-1), proving that the urban area was a significant net source of N(2)O for the period in question.