Title: Waste sorting behaviour in households: a behaviour change theory-driven randomised controlled field trial

Authors: Mohtasham Ghaffari; Sakineh Rakhshanderou; Samira Ghorbani; Saeed Motesaddi Zarandi

Addresses: School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran ' School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran ' School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran ' School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Abstract: Environmental preservation, a key human rights element, necessitates effective waste management due to modern challenges. This randomised field trial investigated the impact of an educational intervention based on the expanded theory of planned behaviour (ETPB) on waste sorting behaviour among 168 Iranian households (79 experimental, 89 control), selected via cluster random sampling. Data were collected using a valid ETPB-based questionnaire before and two months after a 6-week intervention involving lectures, discussions, role-playing, pamphlets, videos, and text messages. Analysis with SPSS version 16, using paired t-tests, independent t-tests, and ANCOVA (P < 0.05), showed no significant pre-intervention differences between groups. Post-intervention, the experimental group exhibited significant improvements in knowledge, attitude, perceived behavioural control, perceived barriers, behavioural intention, and behaviour (P < 0.05), except for subjective norms. The control group showed a significant decline in attitude and behaviour (P 0.001). ETPB-based interventions effectively promote waste sorting, though in-person programs with influential members are recommended to enhance subjective norms.

Keywords: health education; expanded theory of planned behaviour; ETPB; waste sorting; in source separation.

DOI: 10.1504/IJEWM.2026.155085

International Journal of Environment and Waste Management, 2026 Vol.40 No.3, pp.295 - 309

Received: 06 Nov 2024
Accepted: 02 Jun 2025
Published online: 27 Jul 2026 *

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