To estimate the prevalence of tobacco consumption and secondhand smoke (SHS) exposure in private cars, commercial vehicles and taxis in the city of Barcelona in Spain.
Design setting and participants
We carried out an observational cross-sectional study in 2011. We selected a systematic sample of 2442 private cars, commercial vehicles and taxis on 40 public roads regulated by traffic lights in all 10 districts of Barcelona. We calculated the prevalence rates and 95% CIs of smoking and SHS exposure in cars, and the corresponding ORs adjusting for the potential confounding variables.
The prevalence of tobacco consumption was 5.5% (95% CI 4.6% to 6.4%) and was greater for commercial vehicles (9.8%; 95% CI 7.1% to 12.5%). The prevalence of SHS exposure was 5.2% (95% CI 3.8% to 6.6%) and 2.2% (95% CI 0.5% to 3.9%) of passengers under 14 years of age were exposed to SHS in vehicles.
This study highlights the need to promote public health measures aimed at reducing tobacco consumption in vehicles, especially in the presence of children, as well as enforcement of the current Spanish law against smoking in commercial vehicles and taxis.
Tobacco consumption and secondhand smoke (SHS) exposure in vehicles should be targeted because of the high concentrations of SHS due to the confined environment.
Tobacco consumption while driving can also increase the risk of traffic accidents due to driver distraction.
Few studies have used direct observation to examine the consumption of tobacco and SHS exposure in vehicles.
Reducing smoking in vehicles in the presence of children must be prioritised.
Smoking laws should be enforced in commercial vehicles and taxis.
Smoking in vehicles should be recognised by legislation as a distraction.
Strengths and limitations of this study
The main limitation of this study is the inherent observer bias, especially as regards variables such as age, where physical appearance can result in misclassification by the observer.
Obtaining a truly random and representative sample of vehicles in circulation in a city is difficult.
This observational study avoids the information bias generated by the use of self-reported questionnaires.
A pilot study found that direct observational studies are useful for monitoring smoking by motor vehicle drivers.