Real-world applications can be potent tools in chemistry teaching, fostering highly beneficial learning for students. By involving students in real-world phenomena, we not only alter their perceptions of chemistry but also cultivate crucial chemistry competencies, preparing them for the future as scientists and citizens. In this report, we introduce the "Plastic Detective," a citizen inquiry mobile app specifically designed to promote chemistry learning about the circular plastic economy. This app, developed using a user-centered design approach, focuses on engaging young people in environmental science through active inquiry-based chemistry learning. The app allows users to participate in the investigation and monitoring of plastic waste, offering interactive features for data collection, organizing, and sharing. The case studies included in this report detail how students at elementary, secondary, and tertiary levels engaged with the app, demonstrating its ability to enhance their understanding of chemistry concepts and foster environmental stewardship. The findings reveal that students responded positively to the app, as observed through researchers' interactions with participants and informal feedback, indicating noticeable improvements in their attitudes toward chemistry. This highlights the need for accessible technologies that facilitate practical, real-life chemistry learning experiences and a deeper understanding of circular plastic economy concepts.