AirQ+ is a software tool for quantifying the health burden and impact of air pollution. AirQ+ includes methodologies to assess the impacts of short- and long-term exposure to ambient air pollution. The main methodologies use evidence generated by epidemiological cohort studies showing a relationship between average long-term air pollution concentration levels and the mortality risks in exposed populations. Assessing the impact of air pollution is suggested when evaluating the consequences of policies and interventions or of hypothetical scenarios. AirQ+ should always be used with the support of an epidemiologist or air pollution impact assessment expert. To facilitate users in their analyses, AirQ+ comes with manuals that require increasing levels of expertise. AirQ+ is available in English, French, German, Russian and Spanish. Since its launch in 2016, more than 1000 users from 112 countries have downloaded the software, which has been used in over 300 cities.