Air pollution causes cardiac, respiratory, and reproductive problems and is responsible for 2.4 million deaths each year. In the industrialized countries, the emissions of a great many pollutants—though not all—have decreased significantly as a result of industrial slowdown and tighter controls. In Europe, sulfur dioxide (SO2) emissions have dropped by 85% compared with the 1980s, and lead emissions have fallen by more than 96% since the 1990s, thanks to the introduction of unleaded fuel. In developing countries, however, the reverse is true. China has thus become the world’s main polluter, largely due to rapid industrialization and the use of coal-fired power stations.
Nevertheless, it is air pollution inside buildings that is responsible for the majority of deaths—a fact that has only recently come to light. Cooking methods are the principal source of this type of pollution: wood, leaves, coal, and cow dung all release toxic substances and particles when they are burned.
Reductions in air pollution are possible through a few simple measures, such as the use of engines that adhere to pollution standards, chimney filters, and improved cooking methods. But human beings often only react in response to a catastrophe. London’s “Great Smog” of 1952—which was responsible for more than 4,000 deaths in a matter of days—led to the introduction of the first laws against air pollution (the Clean Air Act). This incentive was taken up in the USA and in the majority of Western countries. The Americans also introduced the idea of the pollution permit, a market mechanism that has proved very effective in reducing sulfur emissions (which are also responsible for the acid rain that ravages forests and lakes). This mecha nism prefigured the more recently created trade in greenhouse gas emissions. Air pollution has since become the classic example of an area where the authorities can intervene, in oneway or another, without needing to mobilize public support.