Compliance with the smoking ban in urban public transportation in Chile

INTRODUCTION: The aim of the study is to assess the national level of compliance with the Chilean smoke-free legislation in the urban public transportation system. METHODS: In this cross-sectional observational study, we studied a national representative sample of 475 vehicles obtained through a two-stage cluster sampling design in 2018. First, 57 municipalities were randomly selected, proportionally to the total number of public transportation vehicles. Second, within each municipality, a convenience sample of up to 4 taxis, 4 buses, and 2 metro coaches was observed. We determined the non-compliance level by systematic direct observation of smoking inside the cabin of the vehicle. We estimated the percentage of the visited vehicles where smoking was observed inside the cabin of the vehicle. RESULTS: The observation of metros, buses and taxis was completed in 24, 52, and 48, of the 57 sampled municipalities, respectively. Smoking was observed inside of about 2% of buses and 7% of taxis. Smoking was not observed in metro carriages. Overall, smoking was observed in almost 3% of the vehicles studied. A 3% noncompliance could expose a significant number of persons in public transportation to secondhand smoke, given that every 100 inhabitants results in about 84 rides a day of almost one hour duration. There are few comparable studies to put in an international context our results. In 2018, the year in which we collected the data, WHO considered that compliance with the law in public transportation was maximum. Our compliance estimate was lower, however WHO used a different methodology and its scope also included the inter-urban mobility, which we did not. CONCLUSIONS: The study highlights the need to improve the enforcement of the smoke-free law in the transportation system in Chile, which presently is almost non-existent.