Evaluation of Traffic-Related Air Pollution Exposure in Sensitive Environments

Long-term exposure to traffic-related air pollution is a growing concern in cities worldwide. Vulnerable groups, such as children and the elderly, are recognised as being more susceptible to adverse effects associated with long-term exposure to air pollution. This study establishes a framework to compare two dispersion models, the Gaussian model ADMS-Roads Extra and the hybrid Eulerian–Gaussian model EPISODE-CityChem, in the inner city of Hamburg. Exposure to air pollution in sensitive environments was calculated as time-weighted average based on modelled annual mean concentrations and time-activity data. Both models predicted exposure in different environments in the range of 17–19 µg/m3 for NO2 and 9–10 µg/m3 for PM2.5, exceeding the respective WHO recommendations. Enrolment data of Hamburg’s school administration were used to estimate the potential exposure of school children in the study area. ADMS predicted a larger number of children attending schools that experience the highest NO2 exposure (>17.8 µg/m3), reflecting the stronger roadside concentration gradients simulated by this model. EPISODE-CityChem predicted a larger proportion of school children in the higher PM2.5 exposure classes (>9.38 µg/m3), whereas ADMS allocated a greater proportion to the lower exposure classes, demonstrating the added value of using multi-model approaches in the evaluation of health risks in urban areas.