Continuous emissions monitoring for coal-fired power stations is now required by law in several countries in Europe and in the USA. Measurements of emissions of major pollutants such as particulates, SO2, and NOx are undertaken to ensure compliance of individual sources with emission standards. The data from CEMs are to be used for emissions trading allowances in the USA. In addition to acting as emission watchdogs, CEMs may also provide data for improving plant management and for assessing the efficiency of pollution control equipment. Although CEMs are not used for combustion control, the information they provide can be used . . .