Part II of this Note provides an overview of how the regulatory framework has developed with regard to federal control technology requirements governing major stationary sources. It focuses on the statutory language of the 1970 Clean Air Act and the 1977 Clean Air Act Amendments and subsequent administrative and judicial interpretations. Part III examines the development of the land-use doctrine governing the regulation of preexisting nonconforming uses and highlights its theoretical similarities to the air pollution context. Part IV looks specifically at the jurisprudence surrounding the use of amortization provisions in the zoning context. By and large, a court's acceptance of an amortization provision in the majority of cases hinges on a determination of the reasonableness of an amortization period based on (1) a balancing of public good against private loss and/or (2) the length of the amortization period in relation to the investment. Another important vein of judicial reasoning that emerges on the "reasonableness" of amortization provisions in the takings calculation is what is termed the "amortization-compensation equation." This line of reasoning, popularized in the context of billboard amortization, suggests that the monopolistic position afforded to the owner of a nonconforming use during the amortization period is itself a type of compensation for future loss. Part V proposes that the incorporation of amortization provisions into the Clean Air Act could provide a viable solution to the problem posed by old sources and, if applied properly, is a solution that is both preferable to several proposed alternatives and one that should successfully withstand constitutional takings arguments. Finally, this proposal is framed within the context of a larger debate between the proponents and critics of command-and-control regulation.