Application of the Theory of Planned Behavior to predict waste source separation.

Appropriate solid municipal waste management is an important topic in the EU. Abiding by the amended EU Waste Framework Directive and the amended EU Landfill Directive, Greece has set ambitious goals for waste reuse and recycling and for landfill minimization in its recent National Waste Management Plans. These goals however can only be reached through the improvement of the mixed recyclable waste scheme (the "blue bin" scheme for paper/carton, plastic and metal) and the establishment of collection containers for separate waste streams (separately for biodegradable waste, for glass, for paper/carton and for the rest). Active participation of citizens in waste source separation is paramount for this program. As such, the determinants that favor waste source separation intention were measured in approximately 1600 residents in the city of Thessaloniki in Northern Greece, through the application of the Theory of Planned Behavior (TPB). The determinant of Moral Norms (MN) was included in the basic model [that contains the determinants Attitude (ATT), Subjective Norms (SN) and Perceived Behavioral Control (PBC)]. Each determinant was measured through four or five declarations while the Behavioral Intention (BI) contained ten subsections. The model was able to satisfactorily predict the intention of the respondents to perform waste source separation. Specifically, the model successfully predicted respondents' intention to engage in waste source separation, explaining 36 % of the variance, indicating that a moderate amount of variance can be explained by the constructs. There was a significant direct effect of ATT (β = 0.486, p < 0.001), SN (β = 0.091, p < 0.05), and PBC (β = 0.091, p < 0.05) on BI. Additionally, MN showed statistically significant mediating effects; a mediating effect on BI via ATT (β = 0.479; p < 0.01), via SN (β = 0.046; p = 0.015), and via PBC (β = 0.057; p = 0.017) was noted. Implications of these results on waste separation policies include the following: launching comprehensive public education campaigns to reshape positive attitudes, improving infrastructure to strengthen the real or perceived behavioral control of citizens experience, increasing "peer pressure" via community engagement activities, such as recycling workshops, clean-up drives, and competitions. The important role of moral obligations in the community should be underlined and it may be the long-term key solution; educational programs and campaigns should emphasize the moral obligation of waste separation and integrating environmental ethics into school programs can instill these values from a young age.