Pathway to WHO: Achieving clean air in the UK - Modelling air quality costs and benefits

Background/aim The Clean Air Fund commissioned us to investigate whether the WHO interim target of 10 µg/m3 PM2.5 could be met by 2030 with assessment of the health benefits of these air pollution reductions, to inform consultation on targets for the UK Environment Bill. Methods UK PM2.5 concentrations in 2030 were modelled from 2018 using CMAQ-Urban and emissions predictions from business as usual, electrification of vehicles Planned London specific policies (UK2030+LS1) or two further London scenarios (LS2/3) were added using the London, toolkit model. Life-table analysis at ward level assumed 2030 concentrations were maintained until 2134. Morbidity outcomes from changes in NO2, PM10 and PM2.5 were quantified using summary estimates from the UK Committee on the Medical Effects of Air Pollutants, WHO and published meta-analyses. Monetary values were then applied. Results For UK2030+LS1, concentrations in 2030 were below 10 µg/m3 across the UK except the centre of London, near major roads in cities, and industrial biomass burning locations. With LS2/3, the exceedances dropped to <1% of the area of London. Local authority population-weighted exposures above 10 µg/m3 reduced from 40% in 2018 to 1% in 2030 (UK2030+LS1) to 0% for LS2 and 3. 11.5 million life years were gained across the UK population from 2018–2134 for UK2030+LS1 compared with unchanged 2018 concentrations. 2 million life years were in London, increasing to 2.5 and 2.9 million life years for LS2/3. Substantial health benefits were generated e.g. avoiding 388,000 asthmatic symptom days in asthmatic children and 3,077 new cases of coronary heart disease per year for UK2030+LS1. The monetary benefits showed policies costing up to £383 billion between 2018-2134 would be justified. Conclusions The WHO interim target was met in most but not all locations by 2030 generating substantial health benefits. Keywords PM2.5, WHO Guidelines, air pollution, health impact assessment.