Quantitative Health Impact Assessments (QHIA) can be used to quantify the health benefits of measures to reduce air pollution. One of their key advantages is the ability to estimate the future impact of planned projects or measures currently being implemented. This article describes the results of 16 EQIS aimed at improving ambient air quality, identified in the scientific literature through 2015, and provides examples of numerous applications of this approach. An analysis of the methodological elements—which may vary depending on the nature of the intervention, the evaluation context, and data availability—supports the conduct of intervention-based EQIS designed to inform decision-making. The results of these studies, most of which are encouraging, reinforce and support the measures that have been or are to be implemented.