This educational workbook is designed for students aged 5 to 12 years old to explore and understand indoor air quality and its impact on health and the environment. Developed within the EDIAQI Project (Evidence Driven Indoor Air Quality Improvement), it provides an engaging way to introduce children to complex environmental issues through games, experiments, and creative activities. The workbook includes explanations about key indoor pollutants—such as carbon dioxide, particulate matter, ozone, and volatile organic compounds—along with their sources, effects on human health, and practical strategies to improve air quality. It also incorporates hands-on activities like experiments, observation tasks, word searches, and poster-making to help students internalize knowledge through active learning. This material can be used by teachers, educators, and schools to raise awareness among younger generations about the importance of breathing clean air and taking part in actions that protect their environment. By promoting early education on indoor air quality, it contributes to fostering healthier living environments, community awareness, and societal engagement in environmental health. The workbook supports educational innovation, STEM learning, and citizen science, aligning with European public health and sustainability goals. It can be applied in classrooms, environmental education programs, and outreach activities.