Natural capital accounting of the air quality regulating service by vegetation in the UK

Urban areas are particular hotspots receiving primary and secondary pollutants from rural areas, as well as locally originated pollutants from industry and traffic. Furthermore, high population densities lead to the greatest exposure of the population to air pollution in urban areas. Vegetation, and trees in particular, provide an ecosystem service by removing some of this pollution from the air, thereby reducing exposure of the population and leading to health benefits in terms of avoided mortality and morbidity. However, the magnitude of these benefits is contested. While a number of studies have quantified the amount of pollution removal by trees most use a static approach, assessing pollutant removal and the resulting benefit in situ and for pollutants in isolation. These approaches usually do not take account of the dynamic interactions among pollutants and meteorology, which govern spatial patterns of pollutant removal, or pollutant transport, which determines where the benefits are received. In this study, we apply an atmospheric transport model under two scenarios to calculate the pollution removed by vegetation at a UK scale. We present and discuss initial results on quantities of pollution removed and the resulting change in pollutant concentrations (i.e. pollutant exposure) in the context of other studies.