Exposure of children to second-hand smoke in cars

Objective: To investigate exposure of children to second hand smoke (SHS) in cars under real life smoking and realistic driving conditions. Methods: PM2.5 concentrations (particulate matter with an aerodynamic diameter below 2.5μm) were monitored as a marker for SHS in 21 car journeys using the TSI portable photometer SidePakTM. Five participants (includ ing one non-smoker) volunteered to drive their own cars and were asked to make no changes to their normal smoking behaviour. A child-sized doll was positioned in a child car seat on the back seat of each car. Monitoring took place under different traffic conditions and different ventilation conditions. Results: Geometric mean (GM) PM2.5 concentrations during smoking journeys (65μgm) exceeded the proposed WHO 24-hour guideline concentration for outdoor air pollution (25μgm) and were 10 times higher than those found during non-smoking journeys (6.8μgm). GM PM2.5 concentrations on journeys with low ventilation were 139μgm, whereas for journeys with high ventilation the GM PM2.5 concentration was 32.5μgm . Conclusions: Smoking in cars produces concentrations of PM2.5 that could be classified as unhealthy, even when windows are open or ventilation is on. Based on these findings, measures to prevent smoking in cars, particularly when children are present, should be explored.