There is little doubt that the large-scale utilization of fossil fuels is putting significant stress on the environment. The effects of combustion products on air quality and the climate are both local and global in nature. The local effects, primarily in the form of air pollution and smog formation in large urban areas, have been known for many decades, and in recent years government regulations to reduce the effects of air pollution have been significantly strengthened. These include both exhaust emission standards for vehicles as well as emissions regulations for large fixed installations, such as fossil-fueled power stations. These regulations have been pioneered in the USA by agencies such as the California Air Resources Board (CARB), and the US Environmental Protection Agency (EPA), but similar measures have now been adopted in most of the developed world. On a global scale, there is increasing evidence, and concern, about the role of CO2 and other so-called “greenhouse gases” on global climate change. In this chapter we will examine both the localized and global effects of these air emissions, and describe current mitigation techniques.

LOCALIZED ENVIRONMENTAL CONCERNS

Localized air pollution, prevalent in the heavily populated areas of large cities, results from direct chemical reaction with the products of combustion and from the formation of ground-level ozone. Combustion products include carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), unburned hydrocarbons, and finally carbon dioxide (CO2), which is primarily of global concern.