Personal air pollution exposure during morning commute car and active transport journeys

Abstract

IntroductionCommuting by car in cities during rush hour can potentially result in the commuter being exposed to large concentrations of pollutants. We investigated the differences in pollutant concentrations by commute type in real world journeys in a typical medium-sized city in the UK. MethodsNO2, O3 and PM2.5 concentrations were monitored on weekday morning commutes into Leicester city centre on four routes. A driving commute was made on all four routes and were paired with measurements made via an active commute (either driving or cycling). The average commute exposure to pollutants was determined and the inhaled dosage was estimated. ResultsAverage in-car NO2 concentrations were 30.3 μg m−3and 24.9 μg m-3 higher than that measured in the cycling commutes, and 31.6 μg m−3 and 5.7 μg m−3 higher than average concentrations measured during walking commutes. In-car O3 concentrations were higher than concentrations measured during cycling (8.4 μg m−3, 35.6 μg m−3) and walking commutes (15.5 μg m−3and 33.1 μg m−3). Average in car PM2.5 were 1.8 μg m−3 and 4.3 μg m −3 lower than average concentrations measured during cycling and 1.9 μg m−3 and 1.5 μg m−3 lower than average concentrations measured whilst walking. We calculated higher cumulative doses of pollutants in the active commute compared to the driving commute. However, the health benefits of exercise, through improved physical and mental health as outlined in the literature are expected to outweigh any adverse impacts of the inhaled dosage of pollutants monitored. ConclusionsConcentrations of air pollutants in cars can be considerably higher than concentrations faced by active travellers. Commuters sitting in cars can both miss the benefits of physical activity and be exposed to higher levels of NO2 than in active transport, which is particularly important in countries like the UK with NOx exceedances.