The Dutch Asthma Foundation asked CE to team up with IRAS, the Institute for Risk Assessment Science affiliated with Utrecht University, to prepare an up-to-date review of the scientific state-of-the-art on the health impacts of air pollution and the associated costs to (Dutch) society. The main conclusion is that the health impacts of air pollution cost society at least 4 billion euro a year, with a possible maximum of 40 billion. The bulk of this figure stems from premature mortality due to long-term exposure to airborne particulates. Approximately one-quarter of the figure is associated with (increased) incidence of COPD pathologies and complaints (in particular chronic bronchitis), inflammatory responses of the respiratory tract, reduced lung function and aggravation of chronic pulmonary disorders (including asthmatic attacks). Even short-term exposure can lead to disease and premature death. The report reviews the latest scientific findings on the health impacts of particulates and ozone, in particular, and details the substances and emission sources of greatest significance for air quality. Public health impacts can be traced back mainly to combustion processes (road traffic, shipping, etc.). Finally, the procedure used to calculate the social cost of these impacts is explained. Pivotal here is the expression of a lost year of life, i.e. a reduction in healthy life expectancy, in monetary terms.