The development of a new version of the wire-mesh apparatus, capable of achieving both high heating rates and peak temperatures in excess of 1500 degrees C, has allowed captive sample measurements of N release during devolatilisation under PF combustion conditions to be made for the first time. Both volatile and N release yields differ significantly fi om previous wire-mesh data obtained for peak temperatures in the region of 1000 degrees C. Significant differences are also found in N release patterns between different coal types. Comparison of the high-temperature wire-mesh apparatus N release data with NOx formation data from combustion plant, including full size boilers, shows that differences in NOx formation between coals with similar N contents can be related to their different patterns of volatile nitrogen release.