Simulation of Population-Based Commuter Exposure to NO 2 Using Different Air Pollution Models

We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland), and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO 2 ) as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO 2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD) NO 2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m −3 , range: 21–61) than with a dispersion model with a lower resolution (39 ± 5 µg m −3 ; range: 24–51), and a land use regression model (41 ± 5 µg m −3 ; range: 24–54). Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.