According to an actual estimate, released in March 2014 by the World Health Organization (WHO), about 3.7 million premature deaths were caused by outdoor air pollution worldwide in 2012. If also health effects of indoor air pollution are taken into account, the pollution of air is the largest single environmental health risk on a global scale. Even though air pollution has its largest impact on human health in low- and middle income countries, particularly in South-East Asia, it is also a major health risk in industrialized regions.
A considerable reduction of air pollution was achieved during the last decades in Germany. Today, we can see clear skies even over heavily industrialized regions and ‘Waldsterben’, a German expression for forest decline mainly due to acidic air pollution which has also become a loan word in other languages, seems to be removed from everyday vocabulary. However, it brings back to mind that mitigation of air pollution does not only protect human health, but also ecosystems.
In Germany, the emissions of most air pollutants decreased during the last years. First of all, these successes were achieved by technologies like flue-gas desulfurization or the use of electrostatic precipitators and catalytic converters. The application of these technologies was enforced by emission standards, which are now mainly implemented at European Union level and which are subsequently transferred to national laws and ordinances. These emission standards are mostly aiming at specific plants or motorized vehicles, like large combustion plants or diesel passenger cars. However, a successful air quality policy can not only be based on emission standards.
Once released to the atmosphere, emitted pollutants are dispersed in the air and may react with other air constituents to form secondary air pollutants. Hence, emission levels can only serve as proxies for ambient concentrations of air pollutants, which are directly linked to health outcomes. Therefore, it is also important to directly regulate ambient concentrations of air pollutants. In Germany, the responsibility to meet air quality levels enables local or regional authorities to set up air quality plans containing various measures to improve air quality.