The impact of European measures to reduce air pollutants on air quality, human health and climate

Abstract:

European air quality legislation has reduced emissions of air pollutants across Europe since the 1970s, resulting in improved air quality and benefits to human health but also an unintended impact on regional climate. Here we used a coupled chemistry-climate model and a new policy relevant emission scenario to determine the impact of air pollutant emission reductions over Europe. The emission scenario shows that a combination of technological improvements and end-of-pipe abatement measures in the energy, industrial and road transport sectors reduced European emissions of sulphur dioxide, black carbon and organic carbon by 53%, 59% and 32% respectively. We estimate that these emission reductions decreased European annual mean concentrations of fine particulate matter (PM_2.5) by 35%, sulphate by 44%, black carbon (BC) by 56% and particulate organic matter (POM) by 23%. The reduction in PM_2.5 concentrations is calculated to have prevented 107,000 (40,000-172,000, 5-95% confidence intervals) premature deaths annually from cardiopulmonary disease and lung cancer across the EU member states. The decrease in aerosol concentrations caused a positive all-sky aerosol radiative forcing at the top of atmosphere over Europe of 2.3±0.06 W m^-2 and a positive clear-sky forcing of 1.7±0.05 W m^-2. Additionally, the amount of solar radiation incident at the surface over Europe increased by 3.3±0.07 W m^-2 under all-sky and by 2.7±0.05 W m^-2 under clear-sky conditions. Reductions in BC concentrations caused a 1 Wm^-2 reduction in atmospheric absorption. We use an energy budget approximation to show that the aerosol induced radiative changes caused both temperature and precipitation to increase globally and over Europe. Our results show that the implementation of European legislation to reduce the emission of air pollutants has improved air quality and human health over Europe, as well as altered the regional radiative balance and climate.