Health Effects of Air Pollutants

Although air quality in large cities and industrial areas of Western Europe was deteriorating since the beginning of the industrial revolution in nineteenth century, it was not until the first half of the twentieth century that the adverse health effects of air pollution started attracting scientific attention. Two widely quoted air pollution episodes, the Great London Smog of 1952 and the Meuse Valley (Belgium) episode of 1930, raised public awareness of the potential health effects of air pollution. The London Smog, attributed to the widespread use of coal for domestic heating in London and the stagnant atmospheric conditions prevailing in the capital in December 1952, caused approximately 4,000 premature deaths in a period of around 1 week (representing a 200–300% increase in mortality), with mortality remaining above normal levels for several months after the smog episode. Although air quality has improved a lot since the 1950s due to cleaner fuels, better industrial processes and control technologies, road traffic has emerged as the dominant source of air pollution in developed countries. In December 1991, another winter smog episode induced by similar weather conditions as in 1952 occurred in London causing a 10–25% increase in mortality. In this event, road transport and to a lesser extent domestic heating were the main sources of air pollution. In this Chapter, the health effects of a wide range of outdoor and indoor air pollutants are reviewed based on current toxicological and epidemiological evidence.