Quantifying and valuing the role of UK vegetation in the removal of particulate matter

Air pollution presents a major risk to human health, resulting in premature deaths and reduced quality of life. Vegetation can play a role in reducing concentrations of air pollutants, but estimates of the service that vegetation provides are highly variable. The majority of methods used to calculate pollution removal are driven with static concentrations and therefore ignore the feedback of removal on concentrations, and interactions with wet deposition processes and between compounds. In this study we applied an atmospheric chemistry and transport model (EMEP4UK) to calculate the amount of pollutant removal in the UK by current vegetation for PM2.5, but also gaseous pollutants (NO2, NH3, SO2, O3) by comparing a model run with current landcover to a baseline scenario in which vegetation was replaced by bare soil. From these data we calculated the health benefits from the changes in pollutant concentrations (i.e. change in exposure) induced by the additional pollution removal by the vegetation. Results show that current UK vegetation as a whole reduces concentrations of PM2.5 by around 10%, far greater than in previous studies. The economic value of the health benefits are substantial: £1 billion in avoided health costs estimated for 2015, resulting from 1900 avoided deaths, 27,000 avoided life years lost, 5,800 fewer respiratory hospital admissions and 1,300 fewer cardiovascular hospital admissions. We also show that the benefits do not always occur in the same location as the pollutant removal. In other words the benefits, defined in terms of reduced pollutant concentrations, are also transported in the atmosphere. Copyright © 2018 by the International Aerosol Conference (IAC).