Microplastic exposure, public health, and environmental management: insights from behavioural drivers based on the Theory of Planned Behaviour and Health Belief Model

Microplastics, defined as plastic particles smaller than 5 mm, represent pervasive environmental contaminants of escalating global concern. Nevertheless, public awareness of microplastics risks remains limited. This study employs an integrated framework combining the Theory of Planned Behaviour (TPB) and the Health Belief Model (HBM) to investigate key factors influencing public intentions to reduce microplastics use and their actual behavioural biases. It further categorizes microplastics into six distinct source types, examines the frequency of public exposure to microplastics-containing products, and evaluates awareness of microplastics sources and associated risks. We conducted random face-to-face interviews with 516 respondents in Shanghai. The results show that: (1) The integrated TPB-HBM framework is validated, offering novel insights into public reduction behaviours and extending theoretical applications. (2) Both TPB factors (attitudes, perceived behavioural control, subjective norms) and HBM factors (perceived severity, self-efficacy, perceived benefits) significantly contribute to microplastics reduction behaviours through direct and interacting pathways. (3) Respondents report frequent daily exposure to microplastics sources, demonstrate general consensus regarding these sources, and widely acknowledge the health threats posed by microplastics. Based on these empirical analyses, targeted policy implications and management strategies are proposed to promote public participation in microplastic reduction and enhance waste management.