Lack of assessment in Africa and Asia-Pacific is a major impediment to the understanding, quantification and mitigation of ambient air pollution in the two regions. This project aims at enhancing the capacity of targeted countries in Africa (Benin, Botswana, Ethiopia) and Asia Pacific (Mongolia, Sri Lanka, Thailand) to strengthen and use data and information to assess ambient air quality and support the development and implementation of evidence based policies on ambient air quality and health. The project will address the gaps in knowledge base on ambient air quality and health impacts and connect the two areas, in support of coherent policy making. Building upon lessons learned from earlier initiatives, UNEP will match its comparative advantage in environmental assessment and strengthening of the science policy interface with expert knowledge on public health provided by WHO and UN-HABITAT’s expert knowledge of urban issues. Thereby, the project will help countries transition towards more integrated management of environmental, health and urban issues. To ensure a wide uptake of project results, knowledge will be made available on open platforms including an exchange of data and best practices that promotes collaboration at all levels. Capacity building and the facilitation of technology development and sharing in countries underpins the delivery of all UNEP’s support to countries. This UNEP-led project will help target countries create the necessary enabling environment for sustained ambient air quality assessment to inform evidence-based policy making.