<![CDATA[Poorly managed solid waste poses environmental health risks, while one-way health promotion may be insufficient to foster active public engagement. This study explored the feasibility of a poster competition as a participatory health-promotion strategy and compared waste-management knowledge, attitudes, and practices (KAP) between competition participants and non-participants. The study was conducted in 2026 at Universitas Bhakti Asih Tangerang after a waste-management poster competition. A comparative, observational cross-sectional pilot design was employed, in which participation in the competition was self-selected. Respondents were recruited through convenience sampling, and data were collected using an adapted waste-management KAP questionnaire. Between-group differences were examined using the Mann–Whitney U test (with the rank-biserial correlation as effect size) for knowledge and practice scores, and the chi-square test or Fisher’s exact test (with crude prevalence ratios or Cramér’s V) for categorical items. Participants demonstrated better waste-management knowledge, particularly regarding waste reduction, sorting, and recycling. Intention to participate in waste sorting was also more prominent among participants. However, these differences were not reflected in actual sorting or composting practices. The findings suggest that poster competitions may serve as an entry point for participatory environmental health promotion by strengthening knowledge and intention, but behavioral change requires enabling infrastructure, opportunities for action, habit reinforcement, and sustained support. Because the design was observational and cross-sectional, participants were self-selected, and the groups differed demographically, the findings cannot establish an intervention effect and should be interpreted as preliminary, hypothesis-generating evidence.]]>
