LAUSR

BACKGROUND The increase in non-separated solid waste is a threat to environmental health. People may be motivated to reduce the destructive effects of waste accumulation in the environment by receiving educational messages and learning the proper methods of waste separation. This study aimed to determine the effect of educational messages on waste separation in dormitory students based on Extended Parallel Process Model (EPPM). METHODS This randomized controlled trial was performed on 320 students categorized into four groups from October to December 2019. After installing waste separation tags on separate containers, three types of messages were presented to encourage and educate waste separation in the following four groups: threat messages; efficacy messages; threat/efficacy messages; and control group. Data were collected prior to and one week after training by a self-reported valid and reliable questionnaire. They were analyzed in SPSS21. RESULTS In the efficacy group and threat/efficacy group, not only the mean scores of "perceived threat associated with non-segregation and waste accumulation", "attitude" and "intention" but also the mean score of "efficacy" and "waste separation behavior" were improved (P < 0.05). In both groups, the mean score of "perceived barriers" for waste separation was lower than the other two groups (P < 0.001). DISCUSSION Use of efficacy-based massages alone or in combination with the threat component was proposed to promote waste separation. No specific study has documented the effectiveness of messages based on EPPM on solid waste separation behaviors. The current study highlighted the effectiveness of using EPPM to promote waste-separation behavior in practice, not in theory.