performed as expected the excess no x came from the quench section while the quench flow from the third annulus started to reduce the temperature of the exhaust from the rich section combustion reactions were triggered by the quench air at stoichiometric temperatures by the time the mixing process in the quench section established the low temperature lean region necessary to conclude the combustion reactions there was a 75 80 ppm v no x created during the quench process it follows that increasing the efficiency of the mixing process in the quench section will reduce the no x production there though it may not eliminate it completely projecting the above conclusions obtained from the analysis of the oil burning masb results to the proposed 13 5 ppm v no x atmospheric gas burner case i e reduction of the quench no x by say one third the apg turbine system with the improved masb would obtain single digital no x during the research program mentioned here an experimental rich quench lean burner was also investigated not a masb where the three sections had independent air supplies this burner had similar no x level as the masb about 70 ppm v it could be shown experimentally that by changing the quench airflow reduced residence time in the quench section i e reduced time available for combustion reactions to start there indeed reduced the no x emission.