Cigarette filters, the most commonly littered item worldwide, are one of the main sources of marine pollution. However, reducing cigarette littering is a serious challenge for policy makers and environmental authorities: traditional instruments like bans and fines are generally ineffective. In this article, we evaluate the impact of two interventions aimed at reducing smokers’ littering in public areas, like beaches. We run a field experiment at eight beach resorts in the north east coast of Italy. Resorts were randomly assigned to three groups: in the first, we introduced portable ashtrays to test whether smokers respond to the lower effort costs (time plus inconvenience) by disposing of litter properly. In the second set, we added a social cue. The third group of resorts was used as a control with no intervention. Results suggest that reducing the private costs of a proper disposal through mobile ashtrays significantly affects littering, leading to a reduction of 10–12% in the number of cigarette filters dropped in the sand compared to beaches with no ashtrays. Reinforcing this measure with social prompts does not significantly increase the impact driven by the introduction of mobile ashtrays.
