Emissions of nitrous oxide (N2O) have been analyzed from industrial boilers and from a large experimental combustor buming natural gas, oil, or coal. Production of N2O and production of NOx were observed to be corrrelated, with an average molar ratio of 0.58:1 (N2O-N: NO). The content of fuel nitrogen plays an important role in determining emissions of both N2O and NOx. In conventional single-stage combustors, about 14% of fuel nitrogen is converted to N2O and 24% is converted to NOx. Conversion of fuel nitrogen to N2O was much less efficient (2-4%) in a two-stage experimental combustor and in wood fires. A model is presented describing emissions of N2O globally, from the beginning of the industrial revolution to the present. Combustion of fossil coal in large industrial boilers. The biospheric source of N2O is calculated as 8.8 x 106 t y-1. The tropospheric concentration of N2O in 1860 is estimated to have been 280.7 ppb. We expect that concentrations of N2O should rise more than 20% to about 367 ppb by the year 2050, based on conservative projections of world energy consumption. ¿American Geophysical Union 1987