The report gives results of an experimental investigation of the effects of the interaction between fluid dynamics and chemistry on pollutant formation and destruction in a natural-gas-fired, turbulent diffusion flame burner. The investigation determined the effects of inlet air swirl, combustor pressure, and air/fuel velocity ratio on the time-mean and fluctuating flow field, using probing and optical techniques. Changes in flow field structure were correlated with changes in pollutant emissions from the furnace. The investigation also showed that varying these parameters produces major changes in the time-mean flow field within the burner which significantly influence pollutant formation. It was also discovered that there are substantial large-scale contributions to the total rms turbulent velocity field. These large scale fluctuations result in significant departures from Gaussian turbulence and isotropy in the initial mixing regions of the burner and have pronounced effects on mixing, chemical reaction, and pollutant formation.