Estimates of population exposure to airborne pollutants in a real city: Sensitivity analysis to the spatial resolution of the pollutant concentration and population data

The impact of urban air pollution on human health has become an important problem, and the estimation of the amount of pollutants to which people are exposed is a major challenge, due to the complex spatial distribution of pollutant concentration and the usual coarse spatial resolution data of the population distribution. This study aims to investigate the uncertainties of outdoor population exposure estimates associated to the approach used to assign concentration to population. To achieve this objective, the results of Rivas et al. (2019) are used: 1) the annual average NO2 concentration over the whole city of Pamplona (Spain)computed at high-resolution (~m) by CFD modeling and 2) distribution population from the municipal census, at a resolution of 100m x 100m. Using this detailed information, the population and concentration data were aggregated for different cell resolution, from 100 m x 100 m to 6 km x 5 km (the entire city). The total population exposure was estimated for the different cases and compared with the highest resolution case that was taken as the reference. In addition, the population exposure was estimated using the concentration at the location of different air quality monitoring stations (AQMS). Results suggest that only concentration distributions with equal or finer than 1 km x 1 km provide appropriate estimate of total population exposure. In addition, an in overall, total exposure estimates using concentration at AQMS can induce important errors.