The chapter summarizes EPA's research on emissions and control of persistent organic pollutants (POPs) from combustion sources, with emphasis on source characterization and measurement, formation and destruction mechanisms, formation prevention, and flue gas cleaning. Laboratory experiments conducted to examine polycyclic aromatic hydrocarbon (PAH) emissions from a wide variety of combustion processes, ranging from pulverized coal utility boilers to wood stoves, have shown that they exhibit widely different emission characteristics. Waste incineration research has also shown that complex mechanisms, including physical mixing and chemical kinetics, are involved in the formation of chlorinated products of incomplete combustion (PICs). Research has also indicated that the formation of ultra-trace levels of chlorinated dioxins and chlorinated furans in combustion/incineration processes includes the complex interaction of several factors including temperature, chlorine content, and catalyst. The beneficial effect of sulfur and sorbents for dioxin formation prevention is demonstrated. EPA's effort to develop and evaluate state-of-the-art technologies for on-line measurements of PAHs, volatile PICs, dioxins, and furans is also discussed. The promising potential of applying artificial-intelligence-based control for improving combustion as a POP prevention approach is shown.