Abstract Indoor air quality (IAQ) may have a profound effect on a person’s physical and mental health and well-being. The Knowledge for Indoor Air Quality and Health (K-HEALTHinAIR) project (grant no 101057693) is an interdisciplinary European research project that brings together 15 partners across 8 countries to study the sources, determinants and health outcomes related to IAQ. We aim to increase knowledge and provide input for more accurate monitoring and interventions, promoting healthy indoor air quality across several public health settings. The main aim of this workshop is to engage the public health community in the relevance of IAQ as a public health concern. We will share the innovative and new methodologies applied in the K-HEALTHinAIR project to study IAQ and health and discuss opportunities as well as challenges in this field of research to support shared learning. This workshop highlights IAQ pollutant sources and determinants, seasonal variation in IAQ, older people’s IAQ and health, and presents the project’s open access platform that is developed to share knowledge. We will zoom in on the evidence available for the sources and determinants of exposure to indoor air pollutants. This activity, a systematic review, was fundamental to identify the gaps of knowledge and guide the preparation of data collection tools. It also depicts the main pollutants present in indoor settings and the respective sources and determinants of exposure. Then, one of the 9 public health scenarios studied in the project is presented. We will focus on the first results regarding (determinants of) IAQ variation in primary schools at several locations in Poland. Next, the pilot study in older people living in senior homes in the Netherlands presents first findings of IAQ and health data in this vulnerable population. Finally, the project will deliver an open-access platform aiming to be the one-stop-shop for IAQ Knowledge. The user-profiles identified are presented. At the end, the workshop participants will be up to date on the project’s activities, its relevance for public health and the open access platform via which all output will be shared. Participants will leave with increased understanding of public health research needed to further study IAQ and its impact on health and well-being. Key messages • Indoor air quality is a public health concern impacting health and well-being, especially in vulnerable populations such as children and older people. • The K-HEALTHinAIR project is a multidisciplinary research project in which innovative methodologies are applied to increase knowledge on indoor air quality and health.