It has been demonstrated that the combustion of fossil fuels accounts for 95% of oxides of nitrogen and 90% of black-smoke emissions to the atmosphere over the 1970-1994 period. The study has shown that the overall NOx emissions, over this period, have decreased by a modest 5%. Only the transport sector is seen to have increased its emission of NOx. In contrast, black-smoke emissions are shown to have plummeted by 60% over this period. The overwhelming reason for this has been the decline in the demand for coal in the domestic sector. By 1994, over 50% of NOx and black smoke was generated by road traffic. Petrol has been the major generator of NOx and diesel the main producer of black smoke. Three pieces of legislation were brought into force to limit the emissions from power-generating plant and petrol-driven road traffic. It has been shown that significant reductions in NOx emissions could be achieved in the power-generating sector by the increased use of CCGT and by adopting new energy technology.