According to the World Health Organisation (WHO), environmental air pollution is among the leading risks for noncommunicable diseases worldwide in terms of the global disease burden and the leading environmental cause of disease and death particularly in low- and middle-income countries. Air pollution is a highly complex mixture of various organic and inorganic components from natural and anthropogenic sources, occurring locally or being introduced by longrange transport of pollutants. Moreover, air pollution is modified by regional meteorological conditions. Accordingly, levels and composition of air pollution can vary substantially at a site, nevertheless typically showing a diurnal, weekly and annual cycle. Regulatory limits, as defined by the Air Quality Guidelines of the European Union, are enforced to minimize air pollution associated health hazards for the population. However, legal limits of the European Union clearly exceed the guideline values of the WHO, especially with regard to particulate matter. The burden of ambient air pollution is monitored by means of different indicator pollutants, especially particulate matter up to 2.5m (PM2.5) or 10m (PM10) in aerodynamic diameter, and gases such as nitrogen dioxide (NO2) or ozone (O3). In recent decades, in the western world, decreasing levels of air pollution have been achieved so that the main focus is nowadays on health hazards caused by low concentrations of pollutants. However, in Germany, especially urban areas are still suffering under higher levels of air pollution. In recent decades, a large number of studies have highlighted the harmful effects of air pollution on public health. Primarily, the respiratory and the cardiovascular system are targeted with exposure to higher levels of air pollution being associated with reduced lung function, unspecific respiratory symptoms, increased use of medication and acute exacerbations of lung diseases, myocardial infarction, stroke and even death. Further negative health outcomes such as atherosclerosis, reduced fetal growth, diabetes and limitations of cognitive function and neuronal development are supported by recent studies. Moreover, these studies have substantially improved our understanding of the underlying pathophysiological mechanisms. The 2015 Global Burden of Disease Study underlined the significance of air pollution for public health, particularly in relation to increased morbidity and mortality resulting from chronic diseases. As causal factor for premature death, particularly cardiovascular death, ambient PM2.5 is the number 5 risk factor, well behind the commonly known risk factors elevated blood pressure, smoking, and increased blood levels of glucose and cholesterol. Ambient air pollution is the number 10 risk factor for the disease burden and also the leading environmental risk factor in Germany. Different studies have estimated that ambient air pollution increases mortality and may decrease life expectancy on average by about one year in the European Union. State of the art knowledge on the negative health effects of ambient air pollution and recommendations for environmental safety and health are introduced by this statement of the German Respiratory Society (Deutsche Gesellschaft fur Pneumologie und Beatmungsmedizin). General concepts and health effects concerning the respiratory system are described in the first part of this statement.