Oxy-combustion has a number of advantages over air-fired combustion. When combined with exhaust gas recirculation, it can be used to reduce NOx and increase the concentration of carbon dioxide in the exhaust, allowing for more efficient carbon capture. In this paper, we show that there are additional advantages to oxy-combustion that can be realized. These include stronger combustion and reduced ultrafine PM (soot) formation. These phenomena are not based on flame temperature considerations but rather are a consequence of the changes in flame structure. We explain how such improvements can be realized and give examples based on both modeling and experiment using the counterflow and coflow flame geometries. Results show that oxy-combustion can lead to drastically reduced sooting tendencies, and laser-induced fluorescence measurements show that PAH formation is also reduced. In addition, oxygenenriched flames are found to be 40 times stronger than air-fired flames.