Evaluation of a smoke-free beaches intervention in Barcelona: a quasi-experimental study.

Background: We aim to assess the effect of a smoke-free beaches (SFB) intervention in Barcelona on smoking during the 2021 bathing season.

Methods: Quasi-experimental pre-post design (pre-intervention period: 15-28 May; post-intervention period: 29 May-12 September). Based on users' profiles and location, four beaches were assigned to the intervention group (IG) and five to the comparison group (CG).