Quantifying the effects of exposure to air pollution in terms of public health has become a critical component in policy discussion. WHO/Europe's software tool AirQ+ performs calculations that allow quantification of the health effects of exposure to air pollution, including estimates of the reduction in life expectancy. AirQ+ estimates: - the effects of short-term changes in air pollution (based on risk estimates from time-series studies); - the effects of long-term exposures (using life-tables approach and based on risk estimates from cohort studies).