The present invention includes methods and apparatus useful in the removal of air pollutants. More specifically, this invention relates to methods and apparatus useful in mitigating major air pollutants (SOx and NOx) and trace toxins from coal-fired combustors. Using a method or apparatus of the present invention, a coal-fired combustor may be retrofitted to accommodate combined SOx/NOx removal technology for solid waste reduction and environmentally responsible utilization of dry flue gas (FGD) desulfurization product. The combined SOx/NOx control technology may integrate enhanced removal of SO2 at high to medium temperatures using a desulfurization process of the present invention with selective catalytic reduction technology for NOx. The reactivation of spent sorbent and dry FGD product may result in a more complete utilization of the ash and sorbent in the reduction of SO2 emissions, thereby reducing significantly the amount of sorbent used and the volume of by-product generated. Modifications to a power plant may result in significant changes to the waste stream. Based upon the process for dry FGD product reactivation to achieve enhanced SO2 removal and SCR for NOx removal, it may be possible to remove both sulfur and nitrogen oxides from high sulfur coal. The process is modular in nature (different components of the process can be by-passed as and when the need arises) and thus may have great flexibility and be applicable to various operating conditions.